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ale BUREAU OF ENTOMOLOGY—BULLETIN No, 106. \ | L. O. HOWARD, Entomologist and Chief of Bureau.
‘THE LIFE HISTORY AND BIONOMICS OF SOME q NORTH AMERICAN TICKS.
BY
W. A. HOOKER, F. C. BISHOPP, anp H. P. WOOD.
UNDER THE DIRECTION OF
W. D. HUNTER.
_IssueD SEPTEMBER 7, 1912.
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WASHINGTON: GOVERNMENT PRINTING OFFIOE. 1912.
‘
ee eer OF AGRICULTURE,
BUREAU OF ENTOMOLOGY—BULLETIN No, 106. L. O. HOWARD, Entomologist and Chief of Bureau.
THE LIFE HISTORY AND BIONOMICS OF SOME NORTH AMERICAN TICKS.
BY
W. A. HOOKER, F. C. BISHOPP, anp H. P. WOOD.
UNDER THE DIRECTION OF
W. D. HUNTER.
WASHINGTON: GOVERNMENT PRINTING OFFIOE. 1912,
BUREAU OF ENTOMOLOGY.
L. O. Howarp, Entomologist and Chief of Bureau. C. L. Maruatr, Entomologist and Acting Chief in Absence of Chief. R. 8. Crirrton, Executive Assistant. W. F. Taster, Chief Clerk.
H. CHITTENDEN, 2n charge of truck crop and stored product insect investigations. D. Hopxrins, in charge of forest insect investigations.
D. Hunter, in charge of southern field crop insect investigations.
M. WEBSTER, 1n charge of cereal and forage insect investigations.
L. QUAINTANCE, in charge of deciduous fruit insect investigations.
EK. F. Pures, in charge of bee culture.
D. M. Roaers, in charge of preventing spread of moths, field work.
Roiia P. Currie, in charge of editorial work.
MasBet CotcorD, 1n charge of library.
F. A. W. iB: uN
SOUTHERN FieELD Crop INSECT INVESTIGATIONS. W. D. Hunter, in charge.
F. C. BisHopp, A. H.-Jennines, H. P. Woop, W. V. Kine, engaged in tick investi- gations.
W. D. Pierce, G. D. Smits, J. D. MrircuHett, Harry Prnxus, B. R. Coan, R. W. MoRELAND, engaged in cotton-boll weevil investigations.
A.C. Morean, G. A. Runner, 8S. E. Crump, D. C. Parman, engaged in tobacco insect investigations.
T. E. Hottoway, E. R. BARBER, engaged in sugar cane insect investigations.
E. A. McGreeor, W. A. THomas, engaged in red spider and other cotton insect investi- gations.
J. L. WEBB, engaged in rice insect investigations.
R. A. Cootzy, D. L. Van Dine, A. F. Conran, C. C. KrumBuaar, collaborators.
LETTER OF TRANSMITTAL.
U.S. DEPARTMENT OF AGRICULTURE, BuREAU OF ENTOMOLOGY, Washington, D. C., November 29, 1911.
Srr: I have the honor to transmit herewith a manuscript entitled “The Life History and Bionomics of Some North American Ticks,” prepared by Messrs. W. A. Hooker, F. C. Bishopp, and H. P. Wood, under the direction of Mr. W. D. Hunter, of this bureau. Ticks are of considerable importance in the United States in two respects. Two species are the sole agents in the transmission of certain impor- tant diseases. One of these diseases is the well-known splenetic fever of cattle and the other the Rocky Mountain spotted fever of human beings. The information contained in this manuscript will be of immediate value in connection with the eradication of the cattle tick and also of the form which transmits spotted fever. The remaining species treated in this manuscript are now of importance principally as parasites of domestic animals. In many localities they present serious problems to the farmer. Moreover, there is a possibility that some of the species not known at present to be carriers of diseases will eventually be found to be of importance in connection with disease transmission. For these reasons full information regarding the life history of the various species is in demand.
The work upon which this bulletin is based has extended from 1907 to the present time. The manuscript is intended to be a com- pendium of information regarding ticks which will remain of direct value for many years and make unnecessary the publication of spe- cial bulletins on some of the species treated. .
I recommend that this manuscript be published as Bulletin No. 106 of the Bureau of Entomology.
Respectfully, L. O. Howarp, Entomologist and Chief of Bureau.
Hon. JAMEs WILson, Secretary of Agriculture.
CONTEN ES:
: Page. IIe Re Te DOP R ih oes ie in wp oe Ro Dee Oe iba bake «2 oso 13 manne ie eminence a eh eo 8 SIS 2 Sue's Leap VL .'e 14 Byetematic position and classification: .. 2.0... -. i ee ae ee 14 Collecting, preservaae, and mountmg !). 50.20.5202 848 2b ee ol 17 PiemAgM Te, SIN OTEOD 4 8209S 2025 2822s Seu ys eens a IDOE... - 18 Pintary cn tile wiclomical study of ticke_. 22:2. SPY 20 POs Guicets LMCI oe ot LPR cy tg 21 Getieral life history... -:.22...-2:: 24 erent behead ee a Bae kegel ee elt el lo ee 25 EMR teh oe a a oa en ea hee oe ee ene ease 32 Penne rer) rare Onan a en Se tn a as eens 33 ene RE rs i ee ee Sh aye eg Boe ae aan ete 34 menos empoved in atudies Of ticks...2-. 2.22... 222i... 2. he ents 35 ORES SEEDS tlc os eee i le SRO oh eta op an eR ae 4] ane TIOTENR St Teo tye ke Se Ss aos - ae eat eae AE 44 Rena tient wn ne Arvanidee 25. Jo Se 2 2 2 ek ee ee gece es 45 ot ee Lo ee arg ieee aee oaae ea A eR oh a a 45 Tew tek, Argus mintatus Woclt. 0...) 22. Aen eee dees - 52 46 we GL ED SLs eG oe ee ae ne alle ge pete neemen Neste MWg Fe ies 5s ge Maia aa 46 PS Cae a ae te ene aE RL ee Lea 47 Pecgea pears) chit aiitean 2S oS, a ee wee aw T- - ee MER et ee ee ee oe Ts oa cnt oA SRR a 48 WUC Oe See ee en a ane LE ee OM 59 Pierre MIME IAMCES: 2 52.4 a2 52 to ne SLE Cee 60 ieremeree cnn me ee et CSR ED. Laks SU 60 EE es) ale ee a een oe SC eat el ee 61 TS TS 50 PS pe le eae es eyo tae aie AA ae pelea eae ane A, Ae a 61 The spinose ear tick, Ornithodoros megnini (Dugés)........-.----.----- 61 coll Teh 2. hss teed ee ee eet a olpet hal anaemia i a ogee 62 Host relationship. . Ato. fas kets dh ieee ee ah gm tapes 9 eco ty a 62 Siepueavisiesl distribution: Dich ot et aRla caf m Reli bens decay yp betsy 62 SERN! A See ere he ka renee en 64 aE Ree ra ee or TN ee was 5 a wee Ss oe ws 68 eee AUPE INIENS Sool ial tte Sk es i go a an +S 68 MEM NNCREE Benes te en SF So ee ne we Se mom < 69 Oh eee le dl ee eS See een RE 69 Development of the Ixodide............ : 69 ee EPET TIER ee arin Ci i ote PELE < ois Lien Did nd. w nonce sins 4 oes 7 The black-legged tick, Iwodes scapularis Say...........-.--.--------- 76 Os OAC DN IE ae belle edie a EY One ey yee 76 Host relationship. . : 7 Geographical distribution:. Pe eee nok! oP, vt & eee 77 REE S Se a ee nT Sa ie A hits win nce oe 0 eet ck Cia ns ws 77 ems a tics scree stirs ct teks POPROIE RBUSOA . 6. 3. 81 Senne, TNO TAMER... 52 Salcedo 2 aoe SANS RRS . 81 ME ee sae oe Sat Le. A Tee PER TROON 5 cones 81 en pe Pte cee nace acess aah wees 81
————e ee ae So ee a = I ia a Sea a Rta Nine em cya
6 LIFE HISTORY OF NORTH AMERICAN TICKS.
Development of the Ixodide—Continued. Page. Genus Ixodes—Continued. iti’
The rotund tick, dzodes king? Bishopp-2- 42204 8) seas 2 ee ee ee 82 Descriptive. satis abe Syste oc See ne 82 Host:relationship,..): 2 cceqsdes <e Gee pee ele Oe ee 82 Geographreal distrib wtiome.s 29.7) at eee ee ie ee eee 83 Eafe history eos Pos Che Sava rae oe onto ae eC GI ie gee a ae 83 Lite Cy Cle zo. oes oo PSs eee ee ea 88 Economic importance: 22.602 24 Ub daes Jaa aye ay oe ee 88 Natural. controle 33.50.2355 2 aba ee ee eee alee eee 88
Genus. Heemaphyaalise 2235 sccccec cau 5 «tee Ree eee ee a eee ees 89
The rabbit tick, Hemaphysalis leporis-palustris Packard.............. 89 DOSCTIPUHVCs 2.ahce ssanak eee s tesa ee ee 89 Hostrelationships... es285k.%> sephegi ie See Tere ee ae ee 90 Geographical distributions. 22.252 24. 5) tes eae ee 90 Ethe Mistory 2c52 oji< aceisie ne eee Stee ee 90 . Tater ce yele ss Cou. ct cee Ose te ae eres ae 2 CaN ete ee 95 Hconomic importance: 0322.23.48 cee Sao ee ee 96 Natural. control: . 2 cc. 2. 5s So a ee ee 96
The bird tick, Hemaphysalis chordeilis Packard.................-- eS Tae 97 Descriptive. oo. .2o cle - Oo has ae Oe ee ee ee ee 97 Host relationship... 2... 222 s03.02t eee ee a ee ee 97 Geopraphical distribution: 222252522 oes eae eee 98 Tite history... s2 i) ooo SEAS Cees Ba a ee 98 Life cycle: s.. 352.2002 22r ese ee ee eee 101 Economic importances..\a.252 2 = 254d 22524 fy Ss) eee eee 101 Natural controls.....2082 2 Seer ee ee ee eee 102 Artificial comtroly'¢.4 4.4: S36 5425.9 Sch ee ee ee 102
Genus Rhipicephalus....:.25.9-22es5auc0 Gas ok ee eee eee 102
The brown dog tick, Rhipicephalus sanguineus (Latreille) (teranus
Banks). secusees bec Soe bey eee Oe ee ee eee ee 102 Descripves. <5 eeee ace soe ee SEs ee ee ee eae 103
Host relationships... sce es 5.2 22 se oe eee eee eee 103 Georraphical distabutioni. 24.45.22 oo ee ae eee 104
Wate history: 5.2 yee ns 0 es eee ee a ne 105
Dafoe cyeleceo. «bee si 0s SNS Rs ene ray in nee ae 110 Beonomic importamee. 50 042 oo eee eke te Men nl ye oe 110 Natunaleontrolecsecc a: fe cute is Sas a het a een en eae 110 Antiietal control: 2. 5 lee coe Jabs bee & eee age re ee ea 111
Genus Marearopus ®. 22) bo 2 cee ee. cols oe rere ee ee een ene EE
The North American cattle tick, Margaropus annulatus (Say). .....-- 11 Deseriptives: ..2cck oes Boe en ee eee 111 Host relationship’. :' 2. ee ee ee eae 2 Georeraphical distributions: -2225-222--5 252 satiate tary Bl fo on MSN 112 Life historys22 24 oe ee ea ee 112 Life cycles.) sc 4 oe SC ak Ee reece 116 Economic importance, natural control, and artificial control...... 117
The Australian cattle tick, Margaropus annulatus australis (Fuller)... 117 Deseriptives2.<.c..- ch Set Skis toPod. ho. Deg) eee ea 117 Host relationship: <5 5-06 aces oo ee ee eee 117 Geographical: distribution:-.. 22.55... 2 eee ts See ee 118 Life history. 20:0. 0.55249) 32) bin ae ee a el Pe eee) <2 118 Life cy Cleec 2.2528 oh 2 8 a ee ee ee oe 122 Biconomic importance jo.) oe eee eee oe 122 Natural control 2< =2 - 25.22 She eS: oe ee ee 122
Artificial control 3. c.22.5.0. ae ee ee ee eee eee 123
CONTENTS.
Development of the Ixodiaze—Continued. mM eM ie ok eae sca w crt aeaetyecse ver ose ees
The gopher-tortoise tick, Amblyomma tuberculatum Marx...........--. Ts oie onl abel Plo int ole pg lias he apg ag > elroy She iki ee ae eA aR eek Soi Belek ta cyt ty qe ae eae np Cppmemaemnican GismeIDINIIOR. 52535 ee eee keer enero eg daeuee Pi Be Coes ee eee SiS oS. Se eee re te ae 2a Pe ee ein a ae eae. ok eee ches «% mma MONTANE tice eae eae on le te te bee ks epee Cee eA bee fot er Pan a ee ad ne 2 Got ein 2 an o's ce
The iguana tick, Amblyomma dissimile Koch.............-.--------- Loe er rh cee pepepaeeiete iil papi heh aco pela Melee ebe eieda ms sae Co ee Tn pad a ry Cele, SAL Gaal OO aca Oa ay Sey Geographical distribution...............-. Sls eile I hcp ERMC rae ees ee Ta ee ee eke. Ride | Bo os kia Si Bier eee eee eee) oper) Pees Se hy See ee See creme: SILLINONIIICE oy. 5 2 Se a So Se Se oo a bon doen ooo nse wu DEER ee ce eee Pe. Lares a eee oa ee CESS knw od a2
The Gulf Coast tick, Amblyomma maculatum Koch............------ nem ee eo te Oe PLS WA TIES NE ON See Oe Soe, jE a 8 5 1 amie al pt ee a aia Bees pgs ge gre eeerimeesr dist paton > ras OS Soe eee SO ee ee SLE ET kal ee ll ops cle 9 a iN a els ae tame ryrie... ote Ee RTS Oe Ce Rae eee ern MUADOTEAINCE 2 soa gh ee aS re see es 2 os ele ak DEMIR CEMOE 2 20 CR on ne we eee Sieh. “See ee re yee
The lone star tick, Amblyomma americanum (Linneus)..-...--..----- CETL oS Latches rental ate alae: catia atag anh 1 lg pies ae on gig a Host relationship. ....... Piece ahah Prat 4 hae Le rel ye iene ae Peemersoiscee Cintriuiiitr 9 2 829 Bo ES ee TON Ee CT Oa Me aE At A At eal Me Gy Si Cael ee ae tn ae BS See vee ee CE Pee EL We. eee CEEIIMOPR go 2. Mes eee eee ec bak PieeR ONENESS tree Let, ink nd Spaeth tees Seat Oe
The cayenne tick, Amblyomma cajennense (Fabricius).........---..--
CLP TRI ha hal a Shan SR el SS cal tel Reg nee OE SAT RIL alk i Ral d aet AA lil nie SN Pie ga age aa
Seer irae aPLEIEEIO a en et Se f22 Sess ii kesks
(TEESE SIS GS ag Tela acta: Pee 9 elie asl ie method Se ale Saar Ca eee Rae re ns ws agian se se Gee aes ee MUGGING SOR DOTUBMOE oon pice oo 6 = cee wees wea eee ese Bee. nats iN Se es eg Sk a ce aime mimic ade SIU CRIIEIRT OR Mts Diet he a wseeeeanceesinn one
I i ek ee ew ate weainmieibics
The rabbit Dermacentor, Dermacentor parumapertus marginatus Banks. IPT erie kb we a sare ih tid glk oe welsh sain mameenne® Host relationship. .......... Pe A On eee eee tall «aad PMR ep INMsOIN. . 525. hoo chad. <eadnanet + iesenwe PN WRG ate oad Joe Sad) aR Rah iS «on dn gel kw da - MS aes EEE Wry oe aclsinrs nso eas a CEN ~ SOTA < SARE ave one Economic importance ......... set. dase ae. ue thes Mba “eee SIRT SEMIRECMY era Toc .. sk od CSS. OR Sea Whee ede daemnnacamage.e
8 LIFE HISTORY OF NORTH AMERICAN TICKS.
Development of the Ixodidee—Continued.
Genus Dermacentor—Continued. Page. The Rocky Mountain spotted-fever tick, Dermacentor venustus Banks. 165 Descriptive... 2.22. eppirnae wear ee Sue Os: “oh wR. Et 165 Host-relationship: «42.4.3 decss eas Sage ea 4 ee 166 Geographical distrib wtion. : 2.522 soy elapse) 0 ea ee 2) SS Tate Distory-scsocs oc ree ee ee et ee 168 Lifecycle. ss cnce ie deens Siew Sane Bee ee eee 179 Heononne importance : 0 os. 69o525 52 a eee ee eee eee 180 Natural (comitol a. 2% 2.5. eee eee eee a 180 Artiieral control. o.2 se ee ke eo ee 180 The Pacific Coast tick, Dermacentor occidentalis Neumann..........-- 181 DESETIPUVEL 3. ees. 6 aos eos Le eee 8 oe eee ere ae 181 Flost relationship. .....).222.222 25) 226 eee ee Se ae eee 181 Geographical distributions: 22.22 Soc 6k oc ee ae ee 182 eale dnastary:: ose Hes Sista. cic 2 a te ee a De 2 ste 2 ee Inne eyele 4: s ogceelue Saue faa. teks a ia eeey Sr te ee ee ee 189 Heonomic importance |... 52s eee eee eee eee 189 Natural control .2¢ a2 \cecmges eRe See Ws cee ene aici tee eee 190 Artificial control; . 26.0... 40lne- ce kee s Abe eee ee ae 190 The American dog tick, Dermacentor variabilis (Say). ..-...---------- 190 Deseripiive 203 22 oi ee ee Ee eee ee he a Host relationship . . 02-2258 biee cece eee eee eee ee 191 Geographical disivibution. 92.6252 5.054 eek oe ee 191 Late history; 23. teens 5 Sis Bh ele: piss snes ai te ies ee 191 date eyele. 2 3s uc5 02 eRe Bee Se eee eee 196 Hconomic im portamces: 1-25 a es ee ee ee 197 Natural comirol nfs 40 eee Bee eso Foe ee a ae 197 Artificial comtrol:..5 2252 22s 22s hse ssoesseceet See eee eee ee cee 197 The tropical horse tick, Dermacentor nitens Neumann........-...---- 197 Deseriptive’s ...... 325 .c2ee sce 5) See a ae eae gs tet te eee ee 197 Host celationships 2). 208. a4 oe Siete Galo ee eae nae Megs ae a Ora 198 Geooraphical disteibutions S220. toc 23 eee oe eee 198 Title HIStory... 2c obs bn 92 Ge re a ee 199 ite Cyl. aod oe ao eee Sipe Scene ee ee 203 Reoqnomicimporiance. «3... 22552. octseeee eae eee .. 203 Natural comtrelt. tej cc6 eb) en ee 204 Artificial comtrol: «2... 5. 02.02 aee nee ec eaere ae cee eee See 204 Bibliosraphical references. 2/205 saws A) < Be Se et a ph ay 205
Puate I.
iI.
Ei,
Ty.
vel.
ILLUSTRATIONS.
PLATES.
Apparatus and contrivances used in life-history studies of ticks. Fig. 1.—Rearing cage. Fig. 2.—Bell jar containing attachment cylinder and animal. Fig. 3.—Outdoor attachment and engorge- ment box. Fig. 4.—Dropping cage. Fig. 5.—Bull with harness. Fig. 6.—Dog with collar... a Be Bg: 4 HL cs ae abe
Apparatus used in Hie-history. aeuliess ne tikes *F ig. 1.—Thermo- eraph and apparatus for weather records. Fig. 2.—Pans with glass tubes and pill boxes, in and on moist sand . 5p FOE:
The fowl tick, Argas miniatus: Fig. 1. 2 Uriesinshood Gos. Fig. 2.—Unengorged nymph after first molt. Fig. 3.—Unengorged nymph after second molt. Fig.4.—Engorged nymph after second molt. Fig. 5.—Engorged female, dorsal view. Fig. 6.—Unen- gorged male, dorsal view. Fig.7.—Unengorged male, ventral view. Fig. 8.—Engorged female, ventral view.....................----
The spinose ear tick, Ornithodoros megnini: Fig. 1.—Unengorged larva. Fig. 2.—Slightly engorged nymph, dorsal view. Fig. 3.— Slightly engorged nymph, ventralview. Fig.4.—Engorged nymph, dorsal view. Fig. 5—Engorged nymph, ventral view. Fig. 6.— Engorged female, dorsal view. Fig. 7.—Male, dorsal view. Fig. 8.—Female from which all eggs have been deposited, ventral view. Fig. 9.—Male, ventral view
. The black-legged tick, Ixodes scapularis: Fig. 1.—Unengorged larva.
Fig. 2.—Male, dorsal view. Fig.3.—Male, ventral view. Fig. 4.— Unengorgednymph. Fig. 5.—Partly engorged female, dorsal view. Fig. 6.—Partly engorged female, ventral view. Fig. 7.—Fully engorged female, dorsal view. Fig. 8.—Fully engorged female, ventral view
. The rotund tick, Ixodes kingi: Fig. 1—Unengorged larva. Fig. 2.—
Engorged nymph, dorsal view. Fig. 3.—Engorged nymph, ventral view. Fig. 4.—Male, dorsal view. Fig. 5.—Male, ventral view. Fig. 6.—Unengorged female, dorsal view. Fig. 7—Unengorged female, ventral view. Fig. 8.—Partially engorged female, dorsal view. Fig. 9.—Partially engorged female, ventral view. The brown dog tick, Rhipicephalus sanguineus: Fig. 10.—Unengorged larva. Fig.11.—Unengorged larva. Fig.12.—Unengorged nymph. Fig. 13.—Unengorged female, dorsal view. Fig. 14. view. Fig. 15.—Partially ‘‘deposited-out” female, dorsal view. Fig. 16.—Unengorged female, ventral view. Fig. 17.—Male, TS Cte at te a oa wk os enna ie machen ewnqumness The rabbit tick, Hemaphysalis leporis-palustris: Fig. 1—Unengorged larva. Fig. 2.—Unengorged nymph. Fig. 3—Engorged nymph. Fig. 4.—Engorged female. Fig. 5.—Partially engorged female (balsam mount). Fig. 6.—Male (balsam mount). The bird tick, Hexmaphysalis chordeilis: Fig. 7—Male, dorsal view. Fig. 8.— Male, ventral view. Fig. 9.—Engorged nymph, dorsal view. Fig. 10.—Engorged nymph, ventral view .........-.-...-------+--
9
Page.
40
40
48
64
10
PLATE VIII.
ix.
Mls,
> Gh
SIE
LIFE HISTORY OF NORTH AMERICAN TICKS.
The North American cattle tick, Margaropus annulatus: Fig. 1.— ‘“Deposited-out” female with eggs. Fig. 2.—Unengorged larva.
Page.
Fig. 3—Engorged nymph, dorsal view. Fig. 4——Engorged
nymph, ventral view. Fig. 5.—Unengorged nymph (balsam mount). Fig. 6.—Fully engorged female, dorsal view. Fig. 7.—Male, ventral view. Fig. 8.—Male, dorsal view. Fig. 9.— Unengorged female, dorsalview. Fig. 10.—Unengorged female, ventral view. Fig.11.—Fully engorged female, ventral view.. The gopher-tortoise tick, Amblyomma tuberculatum: Fig. 1.—Un- engorged larva. Fig. 2.—Unengorged nymph. Fig. 3.—En- gorged nymph. Fig. 4.—Engorged female, dorsal view. Fig. 5.—Females engorging on tortoise’s feet. Fig. 6.—Male, dorsal view. Fig. 7—Unengorged female, dorsal view. Fig. 8.—En- gorged female, ventral view
ry
. The iguana tick, Amblyomma dissimile: Fig. 1.—Unengorged
larva. Fig.2.—Unengorgednymph (balsam mount). Fig.3.— Male, dorsal view. Fig. 4.—Unengorged female, dorsal view. Fig. 5.—Fully engorged female (alive). The Gulf Coast tick, Amblyomma maculatum: Fig. 6.—Unengorged larva. Fig. 7.— Unengorged nymph (balsam mount). Fig. 8.—Male, dorsal view. Fig. 9—Unengorged female, dorsal view. Fig. 10.— Eneorged: female, idorsallvaew. 2eooas ance ee. sec eee ee The lone star tick, Amblyommaamericanum: Fig. 1.—Unengorged larva. Fig. 2.—Unengorged female, dorsal view. Fig. 3.— Male (balsam mount). Fig. 4-—Unengorged nymph (balsam mount). Fig.5.—Male, dorsalview. Fig.6.—Engorged female, frontal view. Fig. 7.—Male, ventral view. Fig. 8.—Un- engorged female, dorsal view. Fig. 9.—Unengorged female, ventral view. Fig. 10.—Fully engorged female, dorsal view. . The Cayenne tick, Amblyomma cajennense: Fig. 1.—Unengorged larva. Fig. 2—Unengorged female, dorsal view. Fig. 3.— Male, dorsal view. Fig. 4.—Unengorged nymph (balsam mount). Fig. 5.—Male, ventral view. Fig. 6.—Unengorged female, ventral view. Fig. 7.—Engorged female, dorsal view. The Pacific Coast tick, Dermacentor occidentalis: Fig. 8.—Male, dorsal view. Fig.9.—Male, ventralview. Fig. 10.—Unengorged female, dorsal view. Fig. 11.—Unengorged female, ventral view. Fig. 12.—Fully engorged female, dorsal view...... Ct: The rabbit Dermacentor, Dermacentor parumapertus margin- atus: Fig. 1.—Unengorged larva. Fig. 2.—Unengorged nymph (balsam mount). Fig. 3.—‘‘Deposited-out” female, dorsal view. Fig.4.—Male, dorsalview. Fig.5.—Unengorged female, dorsal view. The tropical horse tick, Dermacentor nitens: Fig. 6.—Unengorged larva. Fig. 7—Unengorged nymph (bal- sam mount). Fig. 8—Engorged female, dorsal view. Fig.
9.—Male, dorsal view. Fig. 10.—Unengorged female, dorsal
view. Fig. 11.—Engorged nymph, ventral view. Fig. 12.— Engorged nymph, dorsal view. Fig. 13.—Engorged female, ventral view. Fig. 14.—Male (balsam mount) .....-... Gemetee
112
124
132
144
152
160
ILLUSTRATIONS,
Prate XIV. The Rocky Mountain spotted-fever tick, Dermacentor venustus:
Fia.
Fig. 1—‘‘Deposited-out” female with eggs. Fig. 2.—Unen- gorged larva. Fig. 3.—‘‘Deposited-out”’ female, frontal view. Fig. 4.—Engorged larva. Fig. 5.—Engorged female, dorsal view. Fig. 6.—Unengorged female, dorsal view. Fig. 7.— Male, dorsal view. Fig. 8.—Male, ventral view. Fig. 9.— Unengorged female, ventral view ........---.-----+--+------
XV. The American dog tick, Dermacentor variabilis: Fig. 1.—Unen-
gorged larva. Fig. 2.—Unengorged nymph (balsam mount). Fig. 3.—Engorged nymph about to molt tofemale. Fig. 4.— Engorged nymph about to molt to male. Fig. 5.—Male, dorsal “view (Texas form). Fig. 6—Unengorged female, dorsal view. Fig. 7.—Male, dorsal view (Oregon form). Fig. 8.—Unengorged female, ventral view. Fig. 9.—Male, ventral view. Fig. 10.— Engorged female, dorsal view. Fig. 11.—Engorged female, RE I ee adh ao isia'n a age Sa wwe oid 2
TEXT FIGURES.
. The fowl tick, Argas miniatus: Distribution in the United States and
earns ae es es PO a eas kaa a cia debe es
. The spinose ear tick, Ornithodoros megnini: Distribution............. . The black-legged tick, Ivodes scapularis: Distribution in the United
SOE RT sar el neo SWE Rit saat aD a od ier a ta eC ie
. The rotund tick, Jvodes kingi: Distribution in the United States . . . The rabbit tick, Hemaphysalis leporis-palustris: Distribution in the
SE SE Swe ile ded Slo et Se ies 1 Baa oe eS po
. The brown dog tick, Rhipicephalus sanguineus: Distribution in the
de a ath a. 5
. The North American cattle tick, Margaropus annulatus: Distribution
Ee ER AO eat hancacnccmiceeanaecawe
. The gopher-tortoise tick, Amblyomma tuberculatum: Distribution... . . The gopher-tortoise tick: Vesica biloba...................--.-.-.-- . The Gulf Coast tick, Amblyomma maculatum: Distribution in the
en Se Ee ee at eS Saline Anke Warten
. The lone star tick, Amblyomma americanum: Distribution in the
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. The Cayenne tick, Amblyomma cajennense: Distribution in North and
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. The rabbit Dermacentor, Dermacentor parumapertus AAO Dis-
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. The Rocky Mountain spotted-fever tick, Dermacentor venustus: Dis-
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. The Pacific Coast tick, Dermacentor occidentalis: Distribution in the
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. The American dog tick, Dermacentor variabilis: Distribution in the
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. The tropical horse tick, Dermacentor nitens: Distribution in North
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11
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164
192
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THE LIFE HISTORY AND BIONOMICS OF SOME NORTH AMERICAN TICKS.
INTRODUCTION,
During the course of investigations of the biology of the North American fever or cattle tick, conducted by the Bureau of Entomology, with headquarters at the field laboratory at Dallas, Tex., many other species of ticks were met with, some of which are of considerable economic importance. In view of their importance as ectoparasites and the part that several are known to play in the transmission of disease, and in view of the further fact that comparatively little was known of their life history and bionomics, it was decided that the investigations should be extended to include as many of the species as possible.
During 1905 a few notes were made upon ticks other than the cattle tick (Margaropus annulatus), which was at that time being studied. These miscellaneous notes were consolidated with those of 1906 during the winter of 1906-7 and published in Bulletin 72 of this bureau, together with the results of studies of the cattle tick. In 1907 fur- ther attention was given to those species which could be obtained for study. During the summer of that year valuable information was received from Prof. C. P. Lounsbury, who visited the laboratory. In 1908 the study of various species was taken up more extensively. The work was confined principally, however, to those species occur- ring in Texas. In 1910 an investigation of the Rocky Mountain spotted-fever tick (Dermacentor venustus) was undertaken by the bureau in cooperation with the Montana Agricultural Experiment Station and the Bureau of Biological Survey. Incidental to the work on the spotted-fever tick studies were undertaken on the life his- tories and habits of a number of species of ticks occurring in the western United States, and several species not herein discussed are at the present time being studied. Our knowledge of the life his-
13
aa. LIFE HISTORY OF NORTH AMERICAN TICKS.
tories of some of these species is rather complete, but it seems desir- able to withhold from publication the results of investigations of these species until further data are accumulated.
This tick investigation has been conducted, throughout, under the general direction of Mr. W. D. Hunter, from whom the writers have received many helpful suggestions. Mr. W. A. Hooker had direct charge of the investigation from its inception until September 15, 1908, when Mr. F. C. Bishopp took direct charge of the investiga- tion and has carried it forward. Mr. H. P. Wood’s connection with the work has been continuous since November, 1907. Mr. J. D. Mitchell and Mr. F. C. Pratt (now deceased) contributed valuable assistance by collecting material and making notes on host relations and economic status. Mr. W. V. King, acting under the direct super- vision of Prof. R. A. Cooley, of the Montana Agricultural Experiment Station, has, by the collection of several hundred lots of ticks in the Northwestern States, supplied a large amount of information on the hosts of Dermacentor venustus and other species and some information upon the geographical distribution of these species. Prof. Cooley has also aided materially in several ways, including the sending of a number of specimens of Ixodes kingi, which were used in the studies of that species published herein. Several correspondents, particularly in the Western States, have furnished a large number of lots of ticks which have been of much value in the work. Mr. C. E. Hood, Mr. G. N. Wolcott, and Mr. G. W. Hood are responsible for a few of the counts of eggs, and these gentlemen, as well as Mr. E. A. McGregor and Mr. J. Jacobs, have assisted in the summarization and tabulation of records.!
CONCERNING TICKS IN GENERAL. SYSTEMATIC POSITION AND CLASSIFICATION.
The ticks form a superfamily of the order Acarina, and are closely related to the mites which produce scab, mange, and itch. The superfamily Ixodoidea, to which all the ticks belong, is composed of two families, namely, the Argaside, represented in this country by 2
1 Credit for taking the photographs used in making the plates in this bulletin should be given as follows:
H. P. Wood: Plate I, fig. 1.
F.C. Bishopp: Plate I, fig. 6; Plate III, fig. 2; Plate XIV, fig. 5.
W.E. Hinds: Plate II, fig. 1; Plate VI, fig. 10; Plate VII, figs. 1, 5, 6; Plate VIII, fig. 5; Plate XI, fig. 3; Plate XIII, fig. 14. j
W. A. Hooker: Plate I, figs. 4, 5; Plate III, figs. 1, 3, 4; Plate V, figs. 1, 4; Plate VI, figs. 11, 12, 15; Plate VII, figs.2, 4; Plate VIII, figs.1, 2; Plate IX, figs. 1-8; Plate X, figs.1-10; Plate XI, figs. 1, 4, 5, 7, 8, 9; Plate XII, figs. 1, 4, 7; Plate XIII, figs. 1-13; Plate XIV, fig. 2; Plate XV, figs. 1-4, 10, 11.
G.N. Wolcott: Plate I, figs. 2,3; Plate II, fig. 2; Plate III, figs. 5-8; Plate IV, figs. 1,9; Plate V, figs. 2,3, 5-8; Plate VI, figs. 1-9, 13, 14, 16,17; Plate VII, figs. 3, 7-10; Plate VIII, figs. 3, 4, 7-11; Plate XI, figs. 6, 10; Plate XII, figs. 2, 3, 5, 6, 8-12; Plate XIV, figs. 1, 3, 4, 6-9; Plate XV, figs. 5-9,
SYSTEMATIC POSITION AND CLASSIFICATION. 15
genera and 6 (possibly 7) species, and the Ixodide, represented by 8 genera, 36 species, and 3 varieties, as follows:
Argas (2 species in the United States). Ornithodoros (4 species in the United States). Rhipicephalus (1 species in the United States). Margaropus(1species in the United States). Rhipicephalinz; Hemaphysalis (2 species in the United States). Dermacentor (8 species and 1 variety in the United States). Ixodes (16 species and 2 varieties in the United States). Ceratixodes (2 species in the United Teodre:.. a. States). Aponomma (1 speciesin the United States). Amblyomma (5 species in the United States).
Argasidze | Ixodoidea...
Ixodide ..
The type locality of 12 of the recognized species occurring in this country is outside of the United States. Of these 12 species 2 were described by Linneeus (1758), 2 by Fabricius (1794), 1 by Leach (1815), 3 by Koch (1844), 1 by Guérin (1849), 1 by Cambridge (1876), and 2 by Dugés (1883).
Many of the names of supposedly new species have proved to be synonyms. Nymphs have occasionally been described as new species. The sexual dimorphism and the variation in the amount of blood en- gorged at the time the specimens were collected account for many of the synonyms. Of the 8 species described by Say in 1821 all but 3 are synonyms or remain unrecognized, while of the 5 described by Fitch (1872) all are synonyms or remain unrecognized. Of the 9 described by kerri (1868, 1869, 1872) 5 are recognized as distinct species.
The first work upon iis classification of the ticks of this country was that of Dr. Marx (1893), whose studies were soon after ter- minated by his death.
In 1896 Dr. L. G. Neumann published the first part of his revision of the Ixodoidea of the world, the last part of which appeared in 1901, but which has been followed from year to year by a series of ‘*Notes.”” Unfortunately this valuable work, in its original form, is accessible to only a few. However, a concise summary has recently been published (1911).
The first great step in the classification of the ticks of thiscountry was taken in 1901, when the important work by Drs. Salmon and Stiles, on the cattle ticks of the United States, was published. With the appearance, in 1908, of the revision of the Ixodoidea of the United
16 LIFE HISTORY OF NORTH AMERICAN TICKS.
States, by Mr. Nathan Banks, a work became available by means of which most of the ticks of this country can be readily identified. Since this work appeared several new species have been described by Messrs. Banks (1910), Stiles (1910), and Bishopp (1911b),?so that at present 42 species and 3 varieties representing the genera Argas, Ornithodoros, Amblyomma, Aponomma, Ceratixodes, Dermacentor, Hemaphysalis, Ixodes, Margaropus, and Rhipicephalus, are known to occur within our borders. A valuable monograph of the Ixodoidea is being published by Nuttall, Warburton, Cooper, and Robinson. Two parts, dealing with the Argasidae, the classification of ticks, and the genus Ixodes, have been issued.
A detailed illustrated account of the general structure of ticks, to which reference should be made, has been given by Salmon and Stiles (1901, pp. 387-398). It may be well, however, to give a brief descrip- tion of the so-called capitulum or head, bearing the palpi and the haustellum, the latter of which consists of the mandibles, mandibular sheaths, and hypostome, which are inserted into the skin of the host. The capitulum is a small subtriangular piece that articulates with the anterior margin and usually within a slight emargination of the corneous shield, or scutum, which in the ixodid female forms the front part of the dorsum and in the male covers the greater part of the body. The hypostome, or labium, which lies underneath the mandibles, is an elongated dart or spatulate structure, which is com- posed of 2 lateral symmetrical halves bearing many hooks or denticles directed backward, so that when embedded in the flesh it can not be forcibly withdrawn with ease. The mandibles, 2 in number, are terminated anteriorly by either 2 or 3 processes, known as apophyses, that are used for piercing the flesh and making an entrance. The mandibular sheaths surround the base of the mandibles and extend backward on the dorsal side of the haustellum. Upon each side of the haustellum, applied closely thereto, are the palpi, which are grooved on the inner margin.
There is considerable variation in the size of the individual ticks of a single species, among both males and females. The engorged nymphs also vary in size, the larger usually being prefemales.? Under the several species measurements will be found which indicate the variation. The color, especially of the immature stages, is also quite variable. In engorged larve and nymphs of some species there is a variation from dark brown to pink and pale gray. This is apparently
1 For the classification of the ticks the worker is referred to Mr. Banks’s Revision of the Ixodoidea (1908). Descriptions of adults, aside from their size and coloration, have been omitted in the present work, as they will be found in Mr. Banks’s Revision.
2 See Bibliographical references, p. 205.
3 The terms ‘‘premale” and “‘prefemale” have been used to denote those individuals, not yet molted to adults, in which the sew can be recognized,
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COLLECTING, PRESERVING, AND MOUNTING. 17
due to the proportionate amount of blood, lymph, and inflammatory exudate that has been engorged.
The internal anatomy of ticks has been studied by a number of investigators, among whom mention should be made of Heller (1858), Pagenstecher (1861), Williams (1905), Allen (1905), Christophers (1906), Bonnet (1907), Nordenskidld (1908, 1909), and Samson (1909).
COLLECTING, PRESERVING, AND MOUNTING.
Owing to the fact that very few entomologists or zoologists have had experience with the systematic collection of ticks a few sugges- tions along this line may prove of value. The writers have found that in many instances zoologists have received and handled speci- mens of skins and living animals to which ticks were attached and entirely overlooked these parasites. In other cases the ticks were seen but were not preserved.. The ease with which this class of para- sites may be preserved should encourage zoologists to keep on the lookout for them and to collect all specimens seen.
Persons who collect specimens of ticks should record the host, point of attachment, date, and locality. All parts of the host, including the inside of the ears, should be closely examined. Upon the discovery of a female, and before removing it, the collector should search closely for the male, which may be attached near by. A pair of forceps will be found useful in removing the smaller ticks. Those with short mouthparts are readily removed without injury, but many, particularly those of the genus Ixodes, are usually so firmly attached that the body of the tick will be separated from the capitulum unless the latter is firmly grasped. Some ixo- dologists have recommended the application of a penetrating oil and waiting for the tick to loosen its hold, but this will seldom be found necessary.
In collecting ticks from small animals which have been shot or trapped, a supply of small cotton bags should be at hand into which the host can be placed as soon as shot and the bag firmly tied to pre- vent the escape of the ticks. In this way specimens may be exam- ined at the collector’s convenience and notes may be made on the habits of the ticks. If the host animal is too large to be bagged it should be examined at once over some white surface, such as white cotton cloth spread over the ground. The importance of immediate examination is emphasized, as the writers have found that larve of the rabbit tick and of other species with short hypostomes commence to leave the host within a very few minutes after the animal is killed. Ticks with long hypostomes, such as Ixodes, are sometimes unable to detach, and therefore remain upon the animal. In a number of
21448°—Bull. 106—12—2
18 LIFE HISTORY OF NORTH AMERICAN TICKS.
instances living and dead ticks have been found clinging to the skins of animals which have been nailed on a wall for several days.
The collection of ticks from herbage, on which they are awaiting a host, may best be done by dragging a white cloth, preferably of wool, over bushes, grass, etc. An ordinary insect beating net may also be employed. Fruitful results have been found to attend the examina- tion of the dens of animals, nests and regular roosting places of birds, and the ground in the vicinity of resting and watering places of mammals. Pill boxes have been found to be satisfactory receptacles for the ticks when collected.
In preserving we have usually used 80 per cent alcohol or a mixture consisting of 60 parts alcohol, 1 part formalin, and 39 parts water. Adult specimens, particularly males with bright color markings, should be mounted on pins, as well as preserved in alcohol. For microscopical study specimens should be mounted in Canada balsam on slides. The contents of the body should first be teased out in hot water, through a slit made at the posterior end of the body. Speci- mens can then be readily cleared by boiling in a 10 per cent solution of caustic potash (KOH), care being taken that the clearing be not carried too far. The method employed by Dr. C. W. Stiles consists in soaking the specimens in from 2 to 5 per cent caustic-potash solution for periods varying from 12 to 96 hours, after which all of the soft body content is removed, and after passing the specimens through water, the alcohols, and xylol or other clearing agents, the specimens are mounted in balsam.
ECONOMIC IMPORTANCE.
Ticks are of economic importance (1) as agents in the transmission of infectious diseases, and (2) as external parasites, both of man and the lower animals. At least two distinct diseases of man and eight or more of domestic animals are known to be thus transmitted, at least 17 species of ticks bemg involved as carriers. Of these dis- eases one of man and one of cattle occur, and one of fowls is sus- pected to occur, in the United States, while several others would undoubtedly obtain a foothold were they once introduced.
It has been estimated by Dr. Mohler (1905) that the cattle tick alone is the source of approximately $40,000,000 annual loss in the United States. Mayer (1906) has estimated the annual loss as nearly $100,000,000. :
These parasites are of considerable importance as external parasites, particularly in the Southern States, owing not only to their irritation and great drain upon stock through removal of blood, but also to their indirect effect as well. In one of Theiler’s experiments (1909a) a horse that was infested with Margaropus decoloratus died as a result of infestation from acute anemia due to the withdrawal of blood.
ECONOMIC IMPORTANCE, 19
Within 3 days 14 pounds, by weight, of ticks which had dropped from this horse were collected, and this amount represented only about one-half of the total number of ticks which engorged upon it. After dropping, their places of attachment furnish points at which the screw-worm fly (Chrysomyia macellaria) deposits its eggs, the mag- gots from which then readily enter the host. In the Southwestern States the appearance of equines is frequently injured by screw- worms, which gain entrance at the points in the ears where ticks had been attached, burrow, and destroy the supporting cartilage, causing the ears to lop over. This condition is commonly known as ‘‘gotched.”’ Not the least of all is the frequent annoyance which man suffers as the result of the attachment of ticks to his body.
The ticks which molt upon the host, instead of having to wait long periods to find another, merely continue sucking blood from the same animal. As a result these ticks reproduce very rapidly and frequently become of much greater importance as external parasites than species which drop to molt. This is the case with the cattle tick. Those which drop to molt have overcome this great disadvantage by becoming more resistant to heat and cold and by having gained the power to withstand much longer periods of fasting. Certain members of the subfamily Ixodine, while not occurring in such great numbers on animals as in the case of species which molt on their hosts—all of which belong to the subfamily Rhipicephaline—are frequently of considerable importance as pests, owing to the fact that the great length of the hypostome permits deep penetration. As the result of this deep penetration by the [xodine, an inflammation is produced which frequently results in suppuration. Often in the attempt to remove ticks belonging to this latter class from the body of the host, the capitulum is separated from the body of the tick and remains embedded in the host.
The periods in the life history of ticks of particular importance economically and which should be determined are: Longevity, or the period required forstarvation while awaiting a host; minimum parasitic period, which is used in connection with the preoviposition and incu- bation periods to determine the time that tick-free areas may be used after infested cattle are turned in before the areas become infested; maximum parasitic pervod, or the period required for cleaning the host of all ticks (except males) when kept in tick-free inclosures; preovi- position period and minimum incubation period, used with the mini- mum parasitic period to determine the time that tick-free lots may be used before becoming infested; stage or stages of imbibition of infec- tion and the stage or stages in which infection is transmitted, i. e., in the case of species involved in disease transmission.
°0 LIFE HISTORY OF NORTH AMERICAN TICKS.
HISTORY OF THE BIOLOGICAL STUDY OF TICKS.
The first studies made of the life history and habits of ticks were those of Dr. Cooper Curtice (1891, 1892a, b) on the cattle tick (Margaropus annulatus) conducted in cooperation with the Texas Agricultural Experiment Station at about the time that Drs. Smith and Kilborne were investigating the réle of that species in the trans- mission of splenetic fever. From the time of these investigations by Dr. Curtice up to 1898 little attention seems to have been given to the biology of ticks other than this species, although a prelimi- nary study was made of Amblyomma variegatum (Hyalomma venustum) in Antigua, by C. A. Barber (1894-95).
In 1898 Dixon and Spreull reported studies made of Margaropus decoloratus and the same year Prof. C. P. Lounsbury, the entomologist of Cape Colony, British South Africa, began his classic studies of the Ixodoidea. Since that time Lounsbury has worked out the life history and habits of a large number of South African species. During the course of these studies he has demonstrated the trans- mission by ticks of three distinct diseases of domestic animals and the pathogenicity of at least seven species of ticks and has determined the stages of imbibition and of inoculation of the hosts with the disease-producing organisms.
In 1898 Dalrymple, Morgan, and Dodson, of the Louisiana Agricul- tural Experiment Station, published a detailed account of experi- ments relating to the life history of the cattle tick. The information which they furnished upon the longevity of the ‘‘seed ticks” served as a basis for the feed-lot and pasture-rotation system for cleaning stock and pastures of the cattle tick. In 1899 Prof. H. A. Morgan published further information upon the life history of the cattle tick and included data upon the biology of Amblyomma americanum, Dermacentor variabilis (electus), and Ixodes scapularis (not ricinus).
In 1899 E. G. Wheler, in England, published an account in which : he reported studies made of Ixodes ricinus and the same year C. J. Pound published notes on the Australian cattle tick (Margaropus annulatus australis). In. 1903, Dr. H. Kossel and his coworkers pub- lished an account of studies of the biology of Jxodes ricinus in a report of investigations made in Germany in which they found it to transmit bovine piroplasmosis. During the course of his investigations of the various protozoan diseases of animals in South Africa, Dr. Arnold Theiler, veterinary bacteriologist to the Transvaal, has added much to our general knowledge of the biology of ticks. Dr. H. T. Ricketts, in connection with his investigation of Rocky Mountain spotted fever, has published information from time to time (1907, 1909a, b) upon the life history and habits of Dermacentor venustus. Prof. R.A. Cooley (1908, 1911) and W. D. Hunter and F. C. Bishopp (1911a, b)
GEOGRAPHICAL DISTRIBUTION. 91
have also published studies made of that species. Capt. S. R. Christophers, working in India, has studied Rhipicephalus sanguineus (1907) and made observations on Ornithodoros savignyi (1906). In South America, Dr. F. Lahille, of Argentina (1905), has studied Margaropus annulatus australis and Dr. C. J. Rohr, of Brazil (1909), has conducted extensive investigations on six species. Newstead reported in 1909 on studies made in Jamaica. Among others who have studied the cattle tick are Ransom (1906), Newell and Dough- erty (1906), Schroeder (1907), Hunter and Hooker (1907), Cary (1908), Cotton (1908), and Graybill (1911). Many others have recorded mis- cellaneous observations on different species. Preliminary notes on several species were published by Hunter and Hooker in 1907, and further information has since been published by Hooker (1908, 1909a, b,c). GEOGRAPHICAL DISTRIBUTION.
The ticks that commonly attach to the domestic animals have been widely disseminated on the hosts so that now many of them are only limited by climatic zones. Of the several meteorologic factors which control their distribution cold appears to be the most impor- tant, although excessive heat and variation in humidity are also important. Thus in America we find the tick species most abundant in the Tropical and Lower Austral zones and the least so in the Boreal Zone. Several native species, notably Margaropus annulatus, Amblyomma maculatum, and Argas miniatus rarely appear above the Lower Austral Zone, while Amblyomma tuberculatum, A. dissimile, A. cajennense, and Dermacentor nitens occur only in the Tropical or Gulf strips of the Lower Austral Zone. Our two species of Ceratixodes, namely, putus and signatus, apparently occur in the Boreal Zone only.
Some species remain attached to their hosts for long periods (par- - ticularly the males) and may be carried great distances. This has resulted in numerous records which must be rejected in determining the normal distribution of a species. The approximate zonal dis- tribution of our species is shown in Table I.
LIFE HISTORY OF NORTH AMERICAN TICKS.
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94 LIFE HISTORY OF NORTH AMERICAN TICKS. GENERAL LIFE HISTORY.
Although ticks are able to survive long periods of fasting—some species much longer than others—development takes place only following a period of attachment during which the blood of some animal, either warm or cold blooded, must be taken into the body, i. e., they are obligatory parasites.. Several writers have considered the possibility that ticks may subsist in part upon vegetable matter. Prof. Lounsbury, however, who has conducted extensive studies of these arachnids, states (1905) that he has no doubt that they derive nutrition exclusively from living animals despite the protracted periods that they often have to wait for hosts. They do, never- theless, imbibe water from the rain or dew upon herbage or from the soil. One of the writers has observed ticks kept in tubes, on dry sand, to imbibe water from the moistened sand. Many untrained observers have reported that engorged ticks give birth to living young. Ricketts (1909a, p. 104) mentions this phenomenon as having been described to him concerning Dermacentor venustus by a number of residents of the Bitter Root Valley, Montana. While the origin of such erroneous statements can not be determined, one explanation to be offered is that of mistaking some of the Kermes for ticks. Thus Kermes galli- formis has been sent to one of the authors by an entomological collector who supposed it to be a tick. With the Kermes was a statement to the effect that it had been found dead with young swarming from it.
DEVELOPMENT.
All ticks pass through four distinct life stages: (1) The egg, (2) the larva or seed tick (6-legged stage), (3) the nymph or yearling tick (first 8-legged stage), and (4) the adult. Ali the ixodid and one (or more) of the argasid ticks engorge and molt but twice before arriving at the adult stage. Two species of Ornithodoros are re- ported to remain inactive in the larval stage and pass the first molt before engorging blood. Some of the argasids molt twice or three times during the nymphal stage, and at least one species continues molting after becoming adult. The larve of Ornithodoros talaje, which species is now being studied, engorge, then drop and molt twice before the next engorgement. The ixodid ticks engorge but once as adults, and die following the completion of oviposition, while most of the argasid ticks engorge a number of times as adults, oviposition following each engorgement.
MOLTING.
HOST RELATIONSHIP. 25
while attached appears to be a special adaptation. One native species (Ornithodoros megnini Dugés) and several exotic species (Rhipicephalus evertsi, R. bursa, Hyalomma zxgyptium) pass the first molt upon the host, but drop for the second. A few species, includ- ing Margaropus annulatus and its several varieties, Dermacentor albipictus and Dermacentor nitens, pass both molts upon the host. As yet none is known to drop for the first molt and to pass the sec- ond upon the host. HABITS.
HOST RELATIONSHIP.
Several species of ticks seem to be naturally restricted to a single genus or family of hosts, such as Hemaphysalis leporis-palustris and Dermacentor parumapertus marginatus to the Leporide. Others, although attaching to some hosts more or less frequently (second- ary hosts), have particular hosts (primary hosts) to which they more commonly attach. From this habit have arisen many of our common tick names, such as the cattle tick, dog tick, rabbit tick, ete.
Ticks occasionally attach themselves to animals which may be termed accidental or temporary hosts. This fact is aptly illustrated by the cattle tick, large numbers of which, in the first experiments, were repeatedly placed upon dogs by the writers, but without becom- ing attached. Finally, however, during the summer of 1908 several ticks attached themselves to the laboratory dogs and later, on these host animals, developed to replete females. There seems to be a rather close analogy between ticks and fleas with regard to hosts. In his revision of the Siphonaptera (1904, p. 368), Baker mentions rabbit fleas as remaining on a human being for some little time, biting frequently while there, but not frequenting the human host nor his clothing or bed. To illustrate how fleas would find these temporary hosts, he mentions the possibility of a rabbit run- ning into a badger hole, or a mouse into a mole burrow; that the eating of a mouse by an owl or the devouring of a rat by a cat would afford favorable conditions for this temporary transference of para- sites. Similar instances account for many of our accidental hosts of ticks. It thus appears that larvee of Amblyomma tuberculatum become attached to hawks and owls at the time their small mammal - hosts are being devoured.
Experiments conducted by the writers have shown that when confined in a bag in close proximity to the scrotum of a bovine, nearly all of the ixodids will attach. As a result of these accidental or temporary attachments for some species we have large host lists, including hosts upon which the ticks could only occasionally or never reach maturity. Prof. Lounsbury has found a peculiar habit in Hyalomma xgyptium impressum. As a larva, it will not feed on the
96 LIFE HISTORY OF NORTH AMERICAN TICKS.
large mammals, but attaches to the heads of fowls and hares, upon which the first molt is passed. Following the second molt, which takes place off the host, it attaches to almost any of the warm- blooded animals.
Mammals serve as the principal hosts of the ticks. Fowls are largely the hosts of the genera Argas and Ceratixodes, of two North American species of the genus Hemaphysalis, and of one of Ixodes. Several species of the genera Ixodes, Amblyomma, Aponomma, and Hyalomma are also occasionally parasitic upon fowls, and in the immature stages a number of others may attach to fowls. A large number of species have been collected from reptiles, several from amphibians, and two from beetles.
ADAPTATIONS.
Natural selection appears to have resulted in special adaptations both of function and structure and of the habits of ticks. All ticks must find hosts and attach at least once, some as many as four times, before they can reproduce. This necessity has resulted in special adaptations of function and structure for attachment.
The adaptation of function is shown in the use made by the ixodid ticks of the front pair of legs. As one approaches the free tick, these legs can be seen waving in the air, while with the others it holds to its support. When a host comes in contact with them, they cling to it most tenaciously with these legs, to determine which fact one has but to pass a finger rapidly over a cluster of the seed ticks. An examination shows the legs to be especially fitted for attachment.
The adaptation of structure for protection is represented in the case of the engorged larve of Argas mimatus. Up to within a few hours of dropping, these larve are globular in shape; but at this time they flatten and assume the typical Argas shape. This flat- tened form, common to all of the other stages, permits the ticks to crawl rapidly and to secrete themselves in cracks and crevices pro- tected from the wily fowl. In the Ixodine we find what may be considered specially adapted mouthparts, which, being unusually long, penetrate deeply and prevent their easy removal. 7
In the adaptation of habits favorable to attachment and protec- tion we find most striking illustrations of natural selection. Such adaptations are: First, in molting; second, in attachment to any host; third, to habits of host; and, fourth, acquired greater vitality. There is a great disadvantage in dropping to molt, for it necessitates long periods of waiting, and results in a high percentage of mor- tality from not finding a host. This disadvantage is overcome by some species which have acquired the habit of molting on the host, for example, by Margaropus and by Dermacentor nitens and D, albipictus.
ADAPTATIONS. 27
To this class belong several other species which have partially over- come this disadvantage by passing the first molt upon the host. Two representatives of this class are the South African species Rhipice- phalus bursa and R. evertsi. It has been overcome entirely by Orni- thodoros megnini, the spinose ear tick, in a somewhat different way— that is, by passing the first molt upon the host, then feeding suffi- ciently as a nymph so that following the second molt, which takes place off the host, engorgement as an adult is unnecessary for oviposi- tion and probably never occurs.
Even in species most diverse in their tastes there are hosts espe- cially favored. This in some cases may be accounted for by the great numbers of that host available. In the class which has adapted its habits to the habits of the host, the ticks are confined largely to a host or group of hosts with similar habits. The species Hemaphy- salis leporis-palustris, commonly known as the rabbit tick, has adapted itself to the habits of the Leporide, the hares and rabbits, and only accidentally attaches to other hosts. It is the habit of the hares and rabbits to remain more or less inactive during the day in their “forms,”’ or resting places, protected by a clump of grass or bushes from ene- mies, such as birds of prey, their activity being largely at night. The writers have found that this tick following engorgement drops largely during the day; in other words, when the hares and rabbits are in their forms or resting places, to which they return to pass the day. Thus, when the ticks have hatched or molted and are ready - to attach, they have little trouble in finding the host. This same habit has been acquired by the fowl tick, Argas miniatus, which, in the engorged larval stage, the writers find, drops only at night (except accidentally), when its host, the fowl, is upon the roost. Thus when ready to reattach it is near and readily finds the host, whereas had it dropped during the day when the fowl was on the “run’”’ the chances of its finding a host would be greatly lessened. A habit apparently acquired by Ornithodoros megnini is that of crawling to a height of several feet from the ground as a nymph before molting and depositing its eggs; thus when the seed ticks appear ready to attach they will be rubbed off by the horses, cows, or other host, and readily find access to the ear. The extreme agility of the unengorged adults of Dermacentor parwmapertus marginatus and Rhipicephalus sanguineus undoubtedly greatly aids these spe- cies in finding a host and in finding a place of attachment before being dislodged by the host. These species furnish what evidence we now have of the adaptation of habits to the habits of the host, but it seems probable that similar habits will be discovered in other species when they have been given sufficient study.
Dr. Nuttall has recently (1911a) discussed a structural adaptation which he believes to have resulted from the interrelationship of
98 LIFE HISTORY OF NORTH AMERICAN TICKS.
the hosts and their parasites. He observes that in certain species — of Ixodes which normally infest wandering animals the hypostomes — of the males are strongly armed, while others which attack animals with fixed habitats have practically no armature on their hypos- tomes. He believes that in some cases the males of these species may never attach to the host. With those species which feed upon wandering hosts, it is necessary for the males, as well as the females,
to attach.
It seems probable that in the species which drop to pass their molts greater resistance to high and low temperatures and the power to withstand long periods of fasting have been acquired. On the other hand, some of the species which have acquired the habit of molting
‘on the host have lost in this power of resistance.
As related to protection, the adaptation of habits may be consid- ered under accelerated engorgement, attachment to favorable part of the host, nocturnal habits, habits while awaiting hosts, and habits during molting and oviposition.
Of accelerated engorgements we have several instances among the ticks. These are best illustrated by the fowl tick, which engorges within a few hours at the most. Prof. Lounsbury argues that such ticks are descendants from forms which remained for days at a time on the host. This view is given weight by the habit of the larve of the fowl tick, of remaining upon the host for several days to engorge. In the cattle tick, Margaropus annulatus, after it has become about one-third engorged, which requires a number of days, complete engorgement takes place and the ticks drop within a com- paratively few hours. In this way the chances of destruction, due to removal by predaceous enemies, such as birds, by crushing by the host, or by attack by parasites, have been very much reduced.
Again we find species which have adapted their habits for pur- poses of protection by attaching to favorable parts of the body, as have Ornithodoros megnini and Dermacentor nitens, which attach to the inside of the ears. The species of Hzemaphysalis found upon quail, field larks, and other ground-feeding birds in Texas, Louisiana, and Florida, appear to attach only to the head, a place from which they are not easily removed by the fowl. Perhaps the most highly developed habit acquired by ticks for protection is the nocturnal habit of species of the genus Argas. Through this habit of resting during the daytime they escape detection by the fowls, which, upon discovering them, devour them with great avidity. At night the fowls go to roost and the ticks have little trouble in finding them and engorging at a time when their hosts are inactive; thus the ticks largely escape detection and destruction.
The habit of the immature stages of the gopher-tortoise tick (Amblyomma tuberculatum) of burying themselves in the soil after
MATING AND FECUNDATION. 29
becoming engorged appears to be an adaptation for protection and to provide moisture for molting.
The clustering of the larvee undoubtedly decreases the rapidity of drying out and thus increases the longevity of that stage. The larvee of Dermacenter albipictus, a species which is now being studied, remain in dense clusters for months on the sand in tubes without making any effort to find a host. This seems to be a protective habit developed in order to pass the time between generations.
The engorged females of most of our species have a habit of find- ing protection as soon after dropping as possible in order that they may deposit their eggs unmolested.
MATING AND FECUNDATION.
Fertilization may take place during attachment or after the females have engorged and left the host. Several instances have been reported in which mating has taken place before attachment to a host, but whether such unions result in fertilization has not been determined. Thus E. G. Wheler (1899, p. 632) collected unengorged specimens of Ixodes ricvnus on herbage which mated when kept in confinement. He also observed mating of a male and an engorged female taken
from a deer.
Mr. J. D. Mitchell, as reported by Hunter and Hooker (1907), observed a pair of Amblyomma americanum clinging to herbage with the mouthparts of the male inserted in the genital orifice of the female, and Mr. C. W. Howard (1909) reports a similar observa- tion in the case of Rhipicephalus ecinctus.
Dr. H. T. Ricketts (1909, p. 99) states that with Dermacentor
_venustus fertilization will take place even when the ticks are not on
an animal host. Just what he intended to convey is not clear, but it would appear that he meant that copulation took place away from the host, probably after removal. The writers have observed this habit in Ixodes scapularis, both upon and off the host. An
_unengorged, unattached female taken in the field from a hunting
dog and placed in a pill box with unattached males taken from the same dog was shortly after found in this relation with one of the males. These observations do not prove, however, that fertiliza- tion follows such unions, and investigations may show that the engorgement of blood by one or both sexes is necessary.
With the Argaside fertilization takes place after the adults have engorged and left the host. Thus the nymphs of Ornithodoros megnini leave the host, molt, and without further feeding are fer- tilized and commence oviposition. Prof. Lounsbury states (1903a, p. 268) that in Argas miniatus mating takes place a few days after engorgement. He says that the male inserts the rostrum into
30 LIFE HISTORY OF NORTH AMERICAN TICKS.
the genital orifice of the female but that he does not know the sig- nificance of this action. We have observed copulation in Argas min- vatus in a number of instances. The act has been witnessed most frequently a few hours after engorgement. The male crawls beneath the female and inserts the hypostome into the female genital orifice. In about five minutes the mouth parts are withdrawn and the male moves slightly forward and deposits a large spermatophore, the end of which is inserted in the female aperture. The contents of the spermatophore appear to be pressed out by the body of the male. The empty spermatophore is usually left attached to the posterior margin of the genital opening of the female. This collapsed sack was found to measure about 0.387 mm. long (parallel with the axis of the tick) by 0.502 mm. broad. Nuttall and Merriman (1911) have made very careful observations on the copulation of Ornithodoros moubata; the process is very similar to that which occurs in Argas miniatus.
With the Ixodide copulation usually takes place on the host, although males of a number of species have been observed with the mouth parts inserted in the genital openings of females while off the host. This habit was first observed by De Geer (1778). Among the ixodid ticks it appears to be the most common in species of the genus Ixodes, having been observed by Wheler (1906, p. 425) in JL. ricinus and J. hexagonus and by the writers in I. scapularis and I. californicus. Samson (1909), who has made observations on this act in Ixodes ricinus, states that no spermatozoa were found in the female genital pore when a male which had its mouthparts inserted was removed. However, males were observed to withdraw the mouthparts and to bring the genital pore into contact with that of the female, then reinsert the beak as though pushing the spermatophore into the female orifice. This habit of the male in introducing the hypostome into the vulva, so commonly observed among species of the genus Ixodes, has been less frequently observed in other ticks. Wheler (1906, p. 425) has also observed the habit in Ceratixodes putus. Donitz (1905, p. 125) reports its occurrence in Rhipicephalus appen- diculatus and BR. evertsi as well as in J. ricinus, and Lounsbury (1905) has observed it one or more times in Amblyomma hebreum, R. evertsi, Margaropus decoloratus, Argas persicus, and Ornithodoros savignyt ceca, as well as in J. pilosus (1900c).
With the species which molt upon the host, the male usually reattaches very shortly after the nymphal skin is shed and, follow- ing a short period of feeding, goes in search of the female. In most of the species which drop to molt it seems to be necessary that the male attach and engorge blood before the sexual instinct becomes manifest. The period required for fecundation appears to vary considerably. Some species, namely, Margaropus annulatus, Der-
EXCRETION. 31
macentor nitens, Rhipicephalus sanguineus, and others, remain mated for nearly the entire period that the female remains attached. Others, including the species of Amblyomma that we have studied, remain in the position of copulation for comparatively short periods.
Considerable difficulty has been experienced by the writers in getting the sexes of the species of Amblyomma and Dermacentor (except D. nitens) to copulate, and there remains much to be learned in relation to this habit.
Prof. Lounsbury has made some interesting observations of the mating of Amblyomma hebreum, a species the habits of which are quite remarkable. He has found that the female goes in search of the male, the latter accepting the female only after having attached and fed for several days.
SECRETIONS.
Several investigators have found that ticks secrete substances that prevent the coagulation of blood. Thus Sabbatini (1898) demonstrated that the bodies of [zodes ricinus, both male and female,
- contain an anticoagulin, and Nuttall and Strickland (1908) demon-
strated the presence of anticoagulin in the salivary glands and intes-
tines of Argas miniatus. Christophers (1906, pp. 10, 45) reports
observations first made by Donovan of a secretion from the coxal
glands of Ornithodoros savignyi when engorging. This secretion, which was abundant (several large clear drops forming in quick - succession), is alkaline to litmus and has a marked effect in prevent-
ing the coagulation of blood. A similar secretion has been observed by the writers to be exuded from the coxal glands of Ornithodoros turicata, O. talaje, and O. megnini. Studies of the glands of ticks
_ have recently been made by Elmassian (1910) and Kiinssberg (1911).
EXCRETION.
All ticks excrete more or less, particularly while attached to a host and engorging. During incubation and when about one-half of the period has passed, a white spot appears at one side of the egg. This spot, which is apparently an excretion of the embryo, is the first gross sign of the viability of the egg. After hatching this excretion still adheres for some time to the anus of the larva, but is finally removed. When seed ticks are hatched out in tubes the sides often become spotted with the white excretions. In the free stage after each molt small drops of either white or black excrement are voided, but it is
during the engorgement of the adults that this is particularly notice-
able. The ticks of the genus Dermacentor are the most offensive in this respect and none can compare with Dermacentor nitens, which, while engorging, constantly excretes a substance which, when dry,
_ resembles coagulated blood.
oo LIFE HISTORY OF NORTH AMERICAN TICKS. CANNIBALISM.
A phenomenon closely related to cannibalism has been observed in a few instances. Hunter and Hooker (1907, p. 35) recorded an observation upon that habit. Among specimens of Margaropus annulatus which had been sent to the laboratory in pill boxes was found a male with its hypostome deeply inserted in the side of an engorged female. Another instance has come to our attention in a figure by C. A. Barber (1895) of Amblyomma variegatum (Hyalomma venustum) showing a male attached to the posterior end of an en- gorged female.
In two instances in the course of our investigation Mr. Wood has observed adults of Ornithodoros turicata to attack and imbibe a large amount of blood from the body of a recently fed adult of the same spe- cies. The specimens from which blood was taken did not seem to be injured by the bite of their fellows.
On April 18, 1910, a box was received at the laboratory which contained two females of Dermacentor venustus taken on a horse at Lakeside, Wash. When received the smaller female, which was shehtly engorged, was attached to the fully engorged individual at a point between the genital opening and the coxa. In the evening of April 18 the small female was found to have detached, leaving the other somewhat distorted in the region of attachment. The injured female began depositing on April 21, but died a few weeks later after laying but 150 eggs, all of which were shriveled and failed to hatch.
MULTIPLICATION.
There is a great variation in the rate of multiplication of ticks, due to the fact that some species pass one or both molts while upon the host, while others drop for both. The ticks which drop for both molts must find a host three separate times before eggs can be depos- ited. Thus their chances of becoming adult are lessened, as compared with the species which pass both molts upon the host, by the propor- tion of 3 to 1. Those which drop to molt have overcome this great disadvantage to some extent through a greater resistance to heat, cold, etc., while awaiting the host, and through depositing larger numbers of eggs. It is well known by zoologists that the number of offspring produced by an animal is in inverse proportion to the chances of their reaching maturity. Thus with ixodid ticks many thousands of eggs are produced. As will be seen by the accompanying table the greatest number of eggs recorded by us as deposited by a single individual was 11,265, which were deposited by Amblyomma maculatum. Mégnin (1904) has recorded 12,000 eggs as being depos- ited by Hyalomma xgyptium, Barber (1895) 20,000 as deposited by Amblyomma variegatum, and Lounsbury (1899) estimates the maxi-
LOCOMOTION AND DISSEMINATION. 33
mum number deposited by Amblyomma hebreum at 20,000. The comparative reproductive capacity of the ticks which we have studied is shown in Table II. )
TaBLe I1.—Reproductive capacity of the species of ticks studied.
Number of eggs deposited.
Number Species. of ticks recorded.| Maxi- | Mini- | Aver- | Maximum number recorded mum. | mum. age. by other observers. Amblyomma americanum............. 12} 8,330 947 | 3,054 | 6,519 (Morgan, 1899). Amblyomma eeaqunene. EE cee rime. 13] 4,789] 2,384] 3,536 | 7,240(Williams by New- stead, 1909). Amblyomma dissimile................- 2 \\ Asap) Gb7orh 19614 jk; 784 (N ewstead, 1909). Amblyomma maculatum.............. 7 | 11,265] 4,560] 8,282 Amblyomma tuberculatum.........-.- 2)\ 1 5,481. |. 2,197 | 3,839 EMEP AS MIMI GUS. ..5 oe cleo ee cee oe ose 21 874 252 537 Mermacentor Nitens «2 <0 esses 12] 3,392| 2,149] 2,784 Dermacentor occidentalis ...........-- 6] 4,555 2,373 | 3,247 aman parumapertus margina- 6 | 4,660 855 | 2, 502 us. Dermacentor variabilis..............-- 11 | 6,855 | 2,808] 4,776 | 7,378 (Morgan, 1899). Dermacentor venustus...............- 11 | 7,396} 2,496] 5,422 320 (Cooley, 1909). Hemaphysalis leporis-palustris.....-- 4] 2,240] 14,112] 1,517 MMAR CS RITES oc Seis a ae cisnvarcla.matcccsis sicicre o Soi) OGn bpaG |) Sn k79 Peoces scapularis... 2.24... ---sce026 0% 11} 3,000} 3,000} 3,000 5,105 (Graybill, 1911). Margaropus annulatus................ 10 | 4,547] 2,127] 3,424 4, 500 (Newell and Dougherty, 1506 Margaropus annulatus australis.....-. 5 | 3,975] 2,492 | 3,072 | 3,046 (Rohr, 1909). Wrmibhodoros Megnini =.=... .+...---. 13 | °1,207 358 760 Rhipicephalus sanguineus............. 12| 2,616 360 | 1,602
1 Number of eggs estimated.
_ Figuring, on the basis of four generations in the Gulf States, that half of the resulting adults are females, and that 2,000 eggs are de- posited by each female, Mayer (1906) has estimated that two Mar- garopus eggs carried over the winter and hatched by April 15 would increase to a total of 6,750,000,000 ticks by October 15, if all the females found hosts and developed. It is at once seen that this is a theoretical estimation, as only a small percentage of the ticks ever
finds a host. LOCOMOTION AND DISSEMINATION.
Experiments have been made by different persons to determine the part that locomotion may play in the dissemination of replete females of the cattle tick. Hunter and Hooker (1907) found them to travel 123 inches in the course of 52 minutes, always traveling away from the light. Engorged females of Dermacentor venustus have been observed by us to crawl as far as 33 inches in 4 minutes. They seem to crawl in the direction in which they are headed without regard to light. The engorged females of all species usually crawl into the first obscure nook, crack, or crevice that they find, and for this reason usually do not travel far from where they drop. Little has been done to determine the distance
21448°—Bull. 106—12 3
34 LIFE HISTORY OF NORTH AMERICAN TICKS.
that ticks may go while in search of a host. Although the dis- tance traveled by seed ticks, as the writers have observed them on grass in cages, is comparatively slight, the adults may be found to crawl considerable distances. This appears to be the case with the brown dog tick (Rhipicephalus sanguineus), which is very agile and constantly moving about when not attached. We have found the males of this species to travel from one dog to another when the hosts were lying asleep in the laboratory. The adults of Dermacentor parumapertus marginatus can crawl considerable dis- tances in a comparatively short time, their movements being very rapid.
The usual method by which ticks are disseminated is by the natural movement of the hosts or by the shipment or driving of the host from one locality to another. The following are good illustrations of how far ticks may be carried upon their usual hosts: The cattle tick has been found on ponies in Michigan, as well as upon cattle at various times in the extreme northern parts of the United States prior to the establishment of a quarantine against this tick. Amblyomma dis- simile has been brought into Texas on iguanas from the Isthmus of Tehuantepec, and according to Barber (1894, 1895) Amblyomma variegatum(Hyalomma venustum) has been introduced into the Leeward Islands on cattle shipped from Senegal,in Africa. That there is abun- dant opportunity for ticks to be carried long distances in this way may be seen from the fact that Ormithodoros megnim has been found to remain upon a host as long as 209 days before dropping. Birds, especially migratory species, may carry ticks long distances. In one instance Mr. W. V. King, of the Bureau of Entomology, found a number of engorged larve of a species of Ornithodoros, which appears to be confined normally to the Southern States, on the head of a bird in northern Wyoming. Among other means of natural dissemi- nation which may be of importance are streams and floods (as men- tioned by Hunter and Hooker, 1907, p. 24), high winds, and the movement of animals which are not hosts but to any of which ticks may cling for a greater or less time. Ticks may be artificially dis- seminated by means of the movement of various farm commodities, especially hay; by crates in which poultry or animals have beencon- fined; by the shipment of hides of animals, and in the clothing of
Man. SEASONAL HISTORY.
RECKONING TEMPERATURE. 35
ton, Mont., late in December and in the first part of January from horses which had been in the hills during the winter. This species is undoubtedly Dermacentor albipictus, which has been found during our investigation to be present on horses and cattle in large numbers in both the nymphal and adult stages throughout the winter months. Thus it appears that even in the Boreal Zone some species are active during the winter months. When the season is not too hot and dry the ticks are most numerous during late summer and early fall. In the case of most of our species, we have found that all stages may occur on hosts at the same time of the year, there being no well- defined restriction of certain stages to any one season.
In our work with Dermacentor venustus we found it almost impos- sible to get adults to attach to hosts durmg the summer months. They remain quiet for long periods with their legs curled up close to the body. This, together with the fact that very few adults are seen on hosts in nature after the middle of June, seems to indicate that there is a period of estivation during the latter part of the summer.
Mayer has considered it possible that the cattle tick, which must find but one host in order to complete its cycle of development, may, where hosts are plentiful, pass as many as four generations in a single year. As the number of generations depends entirely upon the find- ing of hosts, it is impossible to say what the average annual number of generations would be. With the 3-host species, on the average probably not more than one generation is passed in a year, and in many cases a period of two years or even longer may be required for a single generation. -
METHODS EMPLOYED IN STUDIES OF TICKS. RECKONING TEMPERATURE.
Although it is now generally understood that the temperature above which active metabolism takes place in insects, ticks, and other cold- blooded animals may vary with each species or even with each stage in the development of a single species, we have not attempted, in preparing this bulletin, to determine such temperatures, but have thought it best to use 43°F. as the zero of effective temperature in all our computations. However, from the data furnished with each table one can work out the approximate effective temperature for a given stage. In figuring the total effective temperature required for the incubation of eggs we have commenced with the calendar day on which the eggs were deposited and included the day on which hatching occurred. In computing the total effective temperature required for molting we have commenced with the day following dropping and included the day upon which molting took place. The above periods have been used in determining the mean tempera-
36 LIFE HISTORY OF NORTH AMERICAN TICKS.
tures. In reckoning the effective temperature where the daily mean does not fall below 43° F. the average daily mean for the period covered may first be obtained; then, by subtracting 43° F. (the “‘zero”’ of effective temperature) from this mean and multiplying the product by the number of days covered, the total effective tem- perature can be readily calculated. Since the monthly mean tem- perature must first be obtained, by following this method much time may be saved in calculating the total effective temperature. Where the mean temperature for one or more days during a given period falls below the ‘‘zero”’ of effective temperature (43° F.), the effective temperature for cach day should be obtained and added in computing the tetal effective temperature. Our records on the incubation of eggs are based largely upon lots kept in glass tubes on sand.
RECKONING PERIODS.
In determining periods it has been the practice to commence with the day following dropping or hatching of the tick and to include the day oviposition commenced, molting occurred, or death took place, as the case might be. In calculating the period of incubation the day of oviposition as well as the day of hatching has been included, as in the case of the determination of effective temperatures.
In the life-history work in the laboratory it was the daily practice between the hours of 3 and 5 p. m. to separate the eggs from the females,! the molted ticks from those not molted, and to note the hatching of eggs. In case more eggs had been deposited than could be counted within this period, they were isolated in pill boxes and counted the following day. After the eggs were counted they were placed on sand in tubes. Thus the records of egg counts, moltings, and other life changes, as recorded in the tables here given, are for periods of about 24 hours.
In determining the periods of attachment, when these records have been made by the utilization of the bovine scrotum, it has been the practice to place the larve, nymphs, or adults in a cotton bag secured to the host. The bag was examined at periods of 10 to 12 hours and attachment noted. ‘Ticks still in the bag at the end of 24 hours were usually removed. In some cases, however, ticks have been kept in the bag for longer periods, but attention is called to these cases where they occur. Some ticks have been found to remain upon the host for several days unattached or without attaching securely. This might or might not occur naturally, but must be taken mto con- sideration. Where small mammals were employed for the engorge- ment of ticks, in most cases the individuals were examined at frequent intervals, so that the time of attachment was noted rather accurately.
REARING TICKS. 87
This class of animals was usually allowed to remain in the attachment cages for 5 or 6 hours, specimens not attached at the end of that time being returned to rearing tubes.
REARING TICKS.
In rearing ticks one of the first considerations is to eliminate, so far as possible, the danger to the experimenter of infection by disease- bearing species. This requires great care in manipulation, and com- plete isolation, by water and grease or some other substance, of all specimens likely to be infected.
Although it is desirable that the usual host be used in determining the parasitic periods, so that variations from the normal condition may be eliminated, this was not always possible. In a few instances small wild mammals which were captured in nature have been uti- lized for the rearing of ticks and the study of their habits. Animals which have become infested in nature may often be successfully employed in the study of the habits of the ticks with which they are infested. Most of the species which we have studied attach to domestic animals, and as nearly all of these attach to a bovine, we have largely made use of this host in determining the parasitic periods and habits of the species. The method found most satisfactory is that suggested by Prof. C. P. Lounsbury, of attaching a bag over the scrotum of a bovine. In this way the various stages of ticks were applied, examinations made, and the ticks removed as they dropped, and comparatively few were lost. All of the ixodids, except certain species of Ixodes, thus applied by the writers, have attached in one or more stages. Some species, Dermacentor variabilis in particular, attach with considerable reluctance. By removing the bag and with it the unattached ticks at the end of a given period and then replacing the bag and making examinations twice daily and removing the engorged ticks from it, the exact periods of engorgement were deter- mined. In order to prevent the removal of the bag from the scrotum by the host a harness has been employed in some instances and in others leather or wire muzzles have been found satisfactory (Plate IJ). With the ticks which pass both molts upon the host, as do Marga- ropus annulatus, Dermacentor nitens, D, albipictus, and O. megnini, it is a comparatively easy matter to follow the life cycles, but with those which drop from the host to molt, as is the case with most of our North American species, it is much more of a task. With those species which drop for each molt one must succeed in getting the same individuals to attach to the host and catch them as they drop three or more different times. After dropping each time they must be isolated under favorable conditions and frequent examinations made to determine the periods of molting and ovipositing. In order to present satisfactory information upon these periods the periods
88 LIFE HISTORY OF NORTH AMERICAN TICKS.
must be recorded in connection with the thermometric readings, as all life processes when the ticks are off the host appear to be affected by variations in temperature. Our out-of-doors records are based upon temperatures registered by the thermograph shown in Plate II, figure 1. Those indoors were based on a similar thermograph kept in the room with the ticks and regulated by standard thermometers.
In determining the life cycle of ticks that attach to small animals, such as dogs, rabbits, squirrels, fowls, and others, a satisfactory arrangement found has been the use of a cage made of wire of about 41-inch mesh, permitting the ticks to drop through into a pan beneath. (See Pl. I, fig. 4.) This cage, made with a wooden frame, should have the joints set in white lead or putty in order to eliminate all pos- sible hiding places into which the ticks might crawl for protection. Nails inserted in the frame serve as posts, preventing the ticks from crawling back to the cage. In the pan or tray under the, cage may be placed strips of paper, beneath which the ticks will crawl. Some thick and absorbent paper, such as blotting paper or pressing paper, should be placed in the bottom of the tray or pan to absorb the urine. When this is used it is not necessary to eliminate succulent food from the diet of the host animal. It has been the practice to place a ring of white axle grease about the rim of the pan or tray to prevent the escape of any of the ticks which have dropped. Another and more satisfactory way of preventing their escape is by setting this pan or tray in a larger one filled with water. When the examinations are made the tray can be removed, the ticks collected, and the cage cleaned with little difficulty. The plan of this tray was first sug- gested to the writers by Prof. Lounsbury and is similar to that which he has used. A more satisfactory cage than the one just described for use with small hosts, such as guinea pigs and rabbits, has been made by taking two wire desk trays or baskets and fastening them with rubber bands, one bottom side up over the other, as shown in Plate I, figure 1. The principal advantage of this kind of cage over the other is that places for hiding are practically eliminated, thereby allowing quicker examinations. Though the cages may be made of other coarse-mesh wire screen, the desk trays are to be pre- ferred. To prevent the animals from shaking the ticks across the moat an 18-mesh wire-screen band is placed around the cage, with its base set in the tray and the top extending a few inches higher than the cage.
In order to keep the ticks upon or near the host while attaching and to prevent their escape, a canvas cage was used. A square wooden frame was first made, to which the canvas was fitted just tight enough to permit of the removal of the frame so that the canvas bag could be inverted and readily cleaned.
REARING TICKS. 39
It has been found that certain small animals used as hosts for breeding ticks learn after a few infestations to keep up a constant fight against ticks. This habit necessitates special attachment cages and also great care to prevent the ticks from being scratched off after they are once attached. A number of different forms of attachment cages have been devised. The utility of these varies with the individual animal used as a host as well as the species of host and species and stage of ticks applied. In some instances it has been found that successful attachments may be secured by placing the host and ticks in a close-fitting, loose-woven cotton bag with the end tied up. Another method of keeping the host quiet while the parasite is allowed to attach is to put the animal in a cyl- inder of 4-mesh wire. The cylinder should be large enough to be comfortable, but not large enough to allow the animal to turn around. In some cases a rectangular piece of 4-mesh wire is bent into the shape of a V-formed trough about 24 inches on each side and 5 or 6 inches long. This trough-shaped piece is inverted and placed over the back of the animal within the cylinder, the front end being drawn down tightly over the head to prevent shaking. The cylinder con- taining the animal is then placed in an inverted bell jar in a pan surrounded by a moat. (See Pl. I, fig. 2.) The animal is kept in this cage only for a sufficient time to allow the ticks to attach. Small animals which do not fight the ticks may be placed in an inverted bell jar over a moat without using the cylinder. The bell jar should be covered with coarse-mesh screen held down by rubber bands stretched down on different sides to the handle of the jar.
In order to determine the parasitic period of Ornithodoros megnini, cotton bags were fastened about the ears of the host animal and held in place by tying the puckering strings to rings in a cord fastened about the horns, as shown in Plate I, figure 5.
In engorging nymphs and adults of Argas miniatus, it has been found necessary to place a hood about the fowl’s head in order to prevent it from devouring the ticks. Our experience has shown it to be necessary to bind the legs of the fowl sufficiently close together, with a strip of cotton cloth, to prevent an attempt at removing the hood and possible strangulation. Neither the hood of cheesecloth nor the cord, if properly applied, will occasion undue restlessness if the fowl is accustomed to handling.
In applying ticks to tortoises it is necessary to tie a bag about the shell behind the front legs, as otherwise the ticks are likely to be devoured.
While some ticks attach immediately after being placed upon a host, others wander about for some time before attaching, and with some species only part will attach, even though kept for several
40 LIFE HISTORY OF NORTH AMERICAN TICKS.
days in the bag attached to the host. In the observations here recorded those that had not attached at the end of 24 hours were removed from the bag. Others that might not have attached but that were upon the host were permitted to remain. Thus the ' observations reported actually indicate what takes place in nature.
In a few instances rabbits, guinea pigs, and fox squirrels have allowed ticks to become engorged when no provision was made to prevent the host from scratching. Usually, however, special pre- cautions must be taken to prevent the host from displacing the parasites. With most of the small animals, a leather collar has been successfully utilized. These collars are made by cutting out a disk-shaped piece of leather with a hole in the center slightly larger than the neck of the animal. The width of the collar should be at least equal to the distance from the neck to the chin. In applying the collar the ends are lapped and fastened with brass rivets. By keeping the outer edge of the collar circular, the disk takes the form of a truncated cone with base extending forward around the head. (See Pl. I, fig. 6.) When dogs are used, a leather band 4 or 5 inches wide should be placed around the neck behind the other collar so as to keep it forward. In order to protect ticks attached on the ears of rabbits, a disk-shaped collar made of light boards is employed. This collar should be made in two parts, the halves being fastened together with rubber bands so as to permit of removing the collar easily and to make it flexible. ©
As the engorged ticks are removed from the bag or tray, it has been found that favorable conditions for further development are furnished by placing them in pill boxes upon moist sand. These pill boxes are prepared by puncturing the tops and bottoms, or still better, they are furnished with gauze tops, to permit of free circula- tion. Still more favorable conditions are furnished by inserting sand in test tubes from which the bottoms have been removed. The bottoms of tubes may be removed in a satisfactory manner by plunging the tubes into cold water after they have been heated by friction produced by rubbing with a string wrapped around the tube at the point where the cut is desired. These tubes should always be used with those species which, in the immature stages, have a habit of burrowing into the sand before becoming quiescent. As stoppers for the tubes, absorbent cotton will largely prevent too humid an atmosphere, if protected from rains. A large tray, as shown in Plate II, figure 2, has been used filled with sand into which the tubes have been inserted and on which the pill boxes have been kept. By subirrigation the amount of moisture furnished can be kept nearly constant without interfering with the pill boxes. This subirrigation is best furnished by use of a large glass tube extending to the bottom of the sand; water poured into this will gradually per- _ colate through and moisten the entire surface. In most of our
APPARATUS AND CONTRIVANCES USED IN LIFE-HISTORY STUDIES OF TICKS.
Fig. 1.—Rearing cage. Fig. 2.—Bell jar containing attachment cylinder and animal. Fig. 3.—Outdoor attachment and engorgement box. Fig. 4.—Dropping cage. Fig. 5.—Bull with harness. Fig. 6.— Dog with collar. (Original.)
APPARATUS USED IN LIFE-HISTORY STUDIES OF TICKS.
Fig. 1—Thermograph and apparatus for weather records. Fig. 2.—Pans with glass tubes and pill boxes, in and on moist sand. (Original.)
NATURAL CONTROL. 4]
longevity experiments in the laboratory we have used test tubes with the bottoms removed and placed in trays with moistened sand. The mouths of the tubes are closed with absorbent cotton. Observa- tions can readily be made through the glass without disturbing the ticks and the air in the tube is kept moderately humid. For longevity experiments out of doors, we have made use of 14-inch glass tubing cut in lengths of about 10 inches. In one end of these tubes about 2 inches of moist sand and clay is firmly packed to prevent the escape of the ticks through the bottom. These tubes are then set in galvanized-iron cylinders which are sunk into the soil. The soil from the inside of the cylinder is removed to a suffi- cient depth to allow the surface of the dirt in the tube to be on a level with the surrounding earth. In place of an absorbent cotton stop- per a piece of bleached cotton was firmly tied over the top with rough cord, which would stand prolonged exposure without breaking. If exposed to rains but largely protected from the sun during the warmer months the longevity can be determined under normal but favorable conditions. The above methods have also been employed in obtaining preoviposition and oviposition records. Most of the longevity records here reported are based on tube experiments, but in work with Margaropus annulatus we have also placed engorged females collected within 24-hour periods in clumps of grass, about _which screen cages were set to prevent intrusion, and determined
the longevity by recording the dates seed ticks first appeared upon the grass and the dates the last could be found.t
NATURAL CONTROL.
CLIMATIC CONDITIONS.”
Cold appears to be the most effective check upon the spread of some species, while heat and a small or an excessive rainfall are equally effective with others. The effect of atmospheric humidity is undoubtedly an important factor also. Dr. Arnold Theiler (1908) has found the larvee of Margaropus annulatus decoloratus to die within 30 minutes when exposed to a temperature of —5° C. (23° F.) for 48 hours, although they are not affected by an exposure to that tem- perature for 24 hours. We have found that with the cattle tick, engorged females kept in tubes without stoppers were killed at Dallas in October when the temperature fell to 13° F. for a few hours. Eggs of several species of ixodids have been found to be rendered nonviable by exposure to sun on bare ground for a few hours when the atmospheric temperature was about 101° F. The eggs of
1 This can readily b2 done by running the bared hand and arm over the grass.
2 The admirable studies of the cattle tick by Cotton and Voorhees (1911) have come to hand too late to note in this bulletin. Cotton reports that all adults of M. annulatus exposed at 14° F. were killed; that
when unprotected all the larve are killed at 4° F. and all the eggs at 2°. It wasfound that when more than 25 per cent of the original weight of the eggs of this tick is lost they will not hatch.
49 LIFE HISTORY OF NORTH AMERICAN TICKS.
the ixodid ticks often fail to hatch when not supplied with moisture during periods of excessive heat in summer or during dry winters when the incubation period is very long. Flooding apparently has little influence in controlling ixodid ticks, as the larve of M. annu- latus have been found by Hunter and Hooker (1907) to survive a submergence of from 10 to 157 days. Vorontzov (1907) states that the eggs of Ixodes ricinus may retain their vitality under water from fall to spring, and Hunter and Hooker have found the eggs of I. annulatus, when submerged, to hatch in about the normal period.
PREDACEOUS ENEMIES.
Sowbugs, which have been supposed to destroy eggs of ticks, have been shown by Pierce (1907, pp. 17 and 22) to consume compara- tively small numbers even when confined with no other source of food supply. Solenopsis geminata, an ant widely disseminated in this country, is thought to be an important enemy of ticks. Rats and mice feed upon ticks and field mice undoubtedly assist in a limited way in destroying the engorged females. Wellman (1906b) has observed a reduviid bug (Reduvius [Opsicxtus] personatus) feeding on engorged ticks in Africa.
Domestic fowls have been found to destroy cattle ticks that drop about farm buildings and even to jump up and pick them off dairy cows. A hen has been observed by the writers to devour with avid- - ity as many as 150 engorged females of Margaropus annulatus in a half day. Quite a number of species of birds have been observed to light on cattle and feed on the engorged ticks. Several species of blackbird, including the great-tailed grackle or ‘‘jackdaw” (Mega- quiscalus major macrourus), bronzed grackle (Quiscalus quiscula zneus), and Brewer’s blackbird (Huphagus cyanocephalus) are known to do so in Texas. Kingbirds (Zyrannus tyrannus) have been ob- served to do this in Louisiana, and Newstead (1909) reports that in Jamaica the savannah blackbird or tinkling grackle (Quiscalus cras- sirostris) and the ani or ‘“‘parrot-billed blackbird” (Crotophaga ani) have the same habit. McAtee (1911a) states that Mr. H. S. Barber has observed red-eyed cowbirds (Tangavius zneus vnvolucratus), boat- tailed grackles ( Megaquiscalus major), and another species of black- bird picking ticks from cattle at Brownsville, Tex. At Tampico, Mexico, Bishopp observed the groove-billed ani (Crotophaga sulcirosiris) to feed upon Margaropus annulatus australis, attached to cattle. This species and the red-winged blackbird (Agelaius pheniceus) are said by Moreau (1907, figs. 8-9) to prey upon cattle ticks in Mexico. Cherry (1892, p. 325) states that the groove-billed ani habitually feeds upon cattle ticks in Costa Rica. Bendire (1895, p. 435) states that eastern cowbirds ( Molothrus ater) and McAtee (1911b, p. 401) says that the fish crow (Corvus ossifragus) eat ticks. Other birds in the
'*.™=
a Oe Ee el lee
NATURAL CONTROL. 43
stomachs of which the Biological Survey of this department has found ticks (McAtee, 1911a) are the killdeer (Oxyechus vociferus), upland plover (Bartramia longicauda), meadowlark (Sturnella magna), dwarf hermit thrush (Hylocichla guttata nana), and house wren (Troglodytes zdon). Mr. J. D. Mitchell states that it is the habit of jackdaws to search for and destroy many cattle ticks on the range by inverting the dried dung, which furnishes a favorable protective covering for this tick. Pycraft has called attention (1910, p. 124) to a depraved habit that such birds may develop, citing the tick bird which occurs in Africa as an example:
Take, for example, the case of the oxpecker or rhinoceros bird (Buphaga africanus), a native of South Africa and generally regarded as a species of starling. This bird is commonly found in intimate association with basking herds of cattle and big game, running about all over the bodies of these creatures in its search for the ticks and other parasites which harbor there. Lately, however, this bird has fallen into dis- grace, since it has extended its attentions to the horses and cattle of the colonists with anything but happy results. It would seem that in removing ticks from the more tender hides of these animals the birds caused wounds, and at the same time gained a taste for blood, with the result that, where horses and cattle are at all numerous, they become severely persecuted by these birds, who now seek not so much to prey upon the ticks as the hosts thereof, which suffer considerably in consequence. Thus we see how easily long-rooted habits may become changed, and how an originally useful instinct may become depraved. The tough hide of the rhinoceros was proof against the beaks of these birds, and consequently nothing but good resulted from their presence, but, as we have shown, a very different state of things began when the . hides of the imported domesticated animals became subjected to a similar inspection. On account of the damage they do the restrictions imposed by Government for their protection have now been removed, but the oxpecker will doubtless long contrive to hold his own in this vast country. The work of the rhinoceros bird in England is performed by the common starling and so far no harm to cattle has been done by reason of injuries inflicted on the hides. Similarly, in East Africa, egrets swarm over the bodies of elephants when they approach the neighborhood of water, apparently, as it has been suggested, for the sake of capturing the various kinds of insects put up by the elephants as they move about.
PARASITES.
Two chalcidoid parasites have been found to attack engorged nymphs. The first of the two, described by Dr. L. O. Howard in 1907 as Izrodiphagus texanus, was reared by Hooker from specimens of engorged nymphs of Hemaphysalis leporis-palustris collected by Mr. J.D. Mitchell from rabbits in Jackson County, Tex. The extent of the parasitism and importance have not been determined. Nymphs subsequently collected in that locality were not parasitized.
The second parasite (Hunterellus hookeri) was described by Dr, Howard in 1908 from specimens reared by Hooker from engorged nymphs of Rhipicephalus sanguineus, collected by Wood from dogs at Corpus Christi, Tex. This species has been found to play an important part in destroying the brown dog tick in southern Texas. As specimens of this latter species have since been reared by Mr. C. W.
44 LIFE HISTORY OF NORTH AMERICAN TICKS.
Howard in Mozambique, it will probably be found to be a widespread insect.
In addition to serving as intermediate hosts for various species of protozoa of the genera Piroplasma, Anaplasma, and Spirocheta, they apparently play the same rdle for filariz, as has been reported by Grassi and Calandruccio (1890), Noe (1908), Baldasseroni (1909), Darling (1910), and Smith (1910).
IMMUNE RACE OF CATTLE.
Cattle with Brahman blood appear to be largely resistant to the attack of ticks. According to Borden (1910) this quality persists in animals with one sixty-fourth of Brahman blood. For this reason and the fact that they do not contract splenetic fever a large number have been imported into this country for breeding purposes in the South.
In regard to these cattle, Mohler and Thompson (1911) state that—
The sebum secreted by the sebaceous glands of the skin has a peculiar odor which seems to be repugnant to insect hfe. The hide, while it may be as thin as in our domestic animals, still appears to be much tougher and is more difficult to penetrate with a hypodermic needle. The hair is quite short and does not provide favorable shelter for the development of ticks. These three factors are probably responsible for the slight amount of tick molestation which these animals experience.
In our native cattle a considerable individual variation in the
susceptibility to tick attack is seen in the same breed of animals. The length of the hair and condition of the skin of the host seem to be the principal factors influencing tick attack.
ARTIFICIAL CONTROL.
Ticks may be controlled by picking or brushing them from the host and destroying them, by smearing or spraying the host with a disinfectant solution, or by dipping the host in a vat which contains a solution sufficiently strong to kill the ticks and not injure the host. For the details relating to these methods reference should be made to bulletins by Mohler (1905, 1906), Graybill (1909), and Hunter and Bishopp (1911b).
The method by which the cattle tick may be eradicated through a rotation (starvation) system suited to the farm or by a combina- tion of rotation and dipping is also described in the bulletins of Mohler and Graybill above mentioned. Additional information will be found in bulletins by Newell and Dougherty (1906), Hunter and Hooker (1907), Cotton (1908), Hunter and Mitchell (1909), and others. Control methods are briefly considered under the several species.
Restriction of the dissemination of some species may be brought about through quarantining the hosts, as has been done with the cattle tick in this country.
_
LIFE HISTORY OF NORTH AMERICAN TICKS. 45 DEVELOPMENT OF THE ARGASIDZ.
The first of the two families of ticks, the Argaside, is represented in the United States by 2 genera and 6 described species. We have studied a representative of each of the genera.'
All of the argasids so far as known, with one exception, pass their molts off the host. The larve of species belonging to the genus Argas that have been studied remain attached to the host for several days while engorging, but the nymphs and adults require only a few hours at most to engorge. The nymphs molt two or three times, following as many engorgements. The adults engorge repeatedly, each engorgement being followed by oviposition. Unlike other species of the genus thus far studied, Ornithodoros megnina engorges and passes the first molt upon the host; as a nymph it remains attached to the host for a long period, then drops, molts, is fertilized, and oviposits without engorging as an adult, shortly after the com- pletion of which it dies. So far as known it is the only species of tick that does not engorge in the adult stage. Two species of Orni- thodoros (savignyi and moubata) are known to pass the larval molt before feeding, the latter molting the larval skin while still in the egg.
The periods of oviposition, incubation, and molting vary with the temperature; for this reason temperature records have been in- cluded in the tables. With the exception of Ornithodoros megnini, the females of the species known engorge and oviposit repeatedly. The longevity of some of the species, particularly those of the genus Argas, is quite remarkable, as is shown in the following table:
TasLe III.—Marimum longevity recorded for ticks of the family Argasidex.
———_—__—
Maximum longevity of stages.2
Species.
Nymph, | Nymph, Larva first second | Adult. stage stage. Days. Days. Days. | Da ys. MRT TUTICU ILS ope a apes craic mre is Sars SER ain orm wid cn sisi oe 164 269 445 880 NENG HADAECINITYE 65 Sioned distin Lo cemelua c'e ues Sm ae lens one BO FE: ooo ae Rae oe ae 638+
Genus ARGAS Latreille.
Six well-established and 4 doubtful species are included in the genus Argas by Nuttall and Warburton in their monograph of the Argaside, miniatus being placed as a synonym of persicus. In addition to miniatus, which we have studied, only one other species, brevipes, is known to occur in the United States, although Argas reflecus has been erroneously reported as occurring here. Several of the species, particularly miniatus and reflexus, are the source of
1 Two other species of Ornithodoros (0. talaje and O. turicata) -re being studied. 2 Longevity of third nymphal stage of A. miniatus not determined.
46 LIFE HISTORY OF NORTH AMERICAN TICKS.
great loss to poultry keepers, due to the removal by them of blood from the fowls, and more particularly because of the transmission by them of spirochetosis.
The species are nocturnal parasites of chickens, geese, pigeons, and other birds and occasionally attack mustenatls. They remain hidden away by day in cracks and crevices, coming out at night from their hiding places to find the fow! host and engorge with blood.
The life history and habits of Argas miniatus! as worked out by Lounsbury in South Africa are practically identical with those of miniatus as determined by the writers. This tick has been shown to be the active agent in the transmission of the causative organisms of spirochetoses (Spirocheta gallinarum and S. anserinum) of chickens, geese, and other fowls.
In the larval stage Argas minatus remains upon the host for several days to engorge, but in the nymphal and adult stages only a few hours at most are required. In miniatus, the only species of Argas whose life history has been followed, there is a second, and in about one-seventh of the individuals a third nymphal molt, as has been shown by Hooker (1909c). As adults, repeated engorgement takes place, each nearly always followed by the deposition of eggs.
THE FOWL TICK.
Argas miniatus Koch.
The common name, fowl tick, is derived from the fact that this species feeds almost exclusively on domestic fowls and is an impor- tant enemy of them.
DESCRIPTIVE.
Adult (Pl. III, figs. 5-8).—Males, unengorged, 4.5 by 3.5 mm. to 6 by 4.5 mm.; engorged, 5.5 by 3.5 by 2 mm. to 7 by 4 by 2.25 mm. Females, unengorged, 5 by 3 mm. to 8.5 by 5.33 mm.; engorged, 6 by 4 by 2 mm. to 12 by 7 by 3 mm.
Nymph (Pl. III, figs. 2-4).—Last stages (2d and 3d nymphal): Unengorged, 3 by 2 mm. to 4 by 2.75 mm.; engorged, (premales) 5 by 3.5 by 2 mm. to 7 by 4 by 2 mm., (prefemales) 6 by 4 by 2 mm. to 8.5 by 5 by 2.6 mm. The normal brown color becomes purplish when blood is engorged. First stage: Unengorged, 2 by 1.25 mm. to 2.5 by 1.5 mm.; engorged, 3 by 2 by 1 mm. to 4 by 3 by 1 mm. Brown, the margins of the body and legs colorless.
Larva (Pl. ITI, fig. 1)—Unengorged, about 0.8 by 0.6 mm., pale yellow to colorless; engorged, 2.2 by 1.5 mm. to 2.5 by 2 mm., dark blue. In one instance a larva dropped on the fourth night follow- ing attachment, and before assuming the flattened Argas shape.
1 We have thought best to refer to the American fowl tick as A. miniatus; recent investigations, hows ever, indicate that it is synonymous with A. persicus, the name of the Old World fowl tick,
i t¢
=?
ell OT A ee a ee eee
PPA
THE FOWL TICK. 47
This individual, after assuming the flattened shape, measured only 1.5 by 1 mm.
Egg.—The average size of 10 eggs measured was 0.72 by 0.65 mm. Spherical, dark brown, shining, smooth.
HOST RELATIONSHIP.
This tick is principally a parasite of poultry. <A single larva was collected by Mr. J. D. Mitchell on a meadowlark in southern Texas, and Mr. F. C. Pratt found a few larve on a wild turkey at Sabinal, Tex. That it may occasionally be found upon mammals and possibly engorge upon and be disseminated by them is shown by the fact that three adults were removed by Mr. J. D. Mitchell from a jack rabbit shot in Maverick County, Tex., in May, 1906.
Lounsbury has found Argas miniatus in South Africa commonly to attack geese, ducks, and turkeys, and he states that it has been reported to attack canaries and ostriches. It is well known in Persia as the Miana bug. Nuttall and Warburton found this tick to engorge on rats and mice, but with difficulty.
In the larval stage these ticks remain attached to the host for several days before dropping fully engorged, but in the nymphal stages and as adults they engorge in a comparatively short time, a few hours at the most, and nearly always at night. The larve appear to prefer the portions of the body where the feathers are sparse, particularly beneath and on the underside of the wings.
Larve placed in a bag on the scrotum of a bovine and left for 24 hours failed to attach. An attempt to engorge larve on pigeons was also unsuccessful. On one occasion a single individual of a num- ber of adults applied to a guinea pig attached and became partially
engorged. GEOGRAPHICAL DISTRIBUTION.
(Fig. 1.)
This tick was originally described by Koch from Demarara. In this country (see fig. 1) it has been found to be a very common species in certain sections of southern Texas, and appears to be so at certain points in Florida, New Mexico, Arizona, and California. The Marx collection contains specimens from Iowa. It is very probable that this and other records of the occurrence of this tick in the Cen- tral States are based upon specimens introduced into that region, the infestation being only temporary. A careful study of the normal distribution of the species in Texas shows that the limit of its eastern range practically coincides with the division between the Lower Sonoran and Austroriparian faunas. It is widely disseminated in the tropical regions of the New World, having been reported from Mexico, Panama, Jamaica, Cuba, Barbados, Antigua, Martinique, Trinidad, Colombia, British Guiana, and Brazil. It is also found in many parts of Africa, Asia, Europe, and Australia.
A8 LIFE HISTORY OF NORTH AMERICAN TICKS,
LIFE HISTORY.
Fria. 1.—The fowl] tick, Argas miniatus: Distribution in the United States and in part of the West Indies. The large dots show localities where the species has been collected in our investigation. The small dots indicate the probable range of the tick. (Original.)
The egg (Tables IV and V).—At summer temperatures at Dallas, Tex., following the first and third engorgements as adults, eggs were deposited as soon as the third day, while after the second engorge-
Bul. 106, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE III.
Fig. 1—Unengorged larva. Fig. 2—Unengorged nymph after first molt. Fig. 3.—Unengorged nymph after second molt. Fig. 4.—Engorged nymph after second molt. Fig. 5.—Engorged female, dorsal view. Fig. 6.—Unengorged male, dorsal view. Fig. 7—Unengorged male, ventral view. Fig. 8.—Engorged female, ventral view. (Original.)
he alte i ba ; an pee. ae x Tat al ’ 5 pe te e - at = a ye « nati, ° CR ee - : _ a ‘ ae . ee, ae i‘ i - : :. re c & - i ‘ ead » uel, ne j - - . - : ‘ . j { t Lr . oe Z - vi » .
— oo THE FOWL TICK. 49
ment eggs were deposited as soon as the second day. In several instances ticks did not oviposit until they had fed a second time. When this occurred in the summer it is thought to have been due to the fact that they had not mated, as females which remained for several weeks after engorging without depositing eggs commenced to do so very shortly after being placed with males. In the winter, however, in some cases females when with males remained for long periods without depositing, but when fed a second time began deposi- tion. During these long preoviposition periods the females flattened considerably, the blood evidently being used by the tick to sustain life rather than in the production of eggs. _ As is shown in Table IV, the greatest number of eggs deposited by any of 21 ticks observed following the first engorgement as adults was 195. The greatest number deposited by any of 21 ticks observed following the second engorgement was 237, and the greatest number deposited by a single tick following the two engorgements, 401. Following the third engorgement 245 was the largest number of eggs deposited by any of the 21 ticks observed. The greatest number of eggs deposited by any one tick following the first three engorgements was 646. The greatest number of eggs deposited by any one of the 20 ticks which were observed following the fourth engorgement was 228. Nine ticks deposited following the fifth engorgement, the greatest number of eggs deposited by an individual being 201. Although four ticks engorged the sixth time only two of these oviposited. One of these deposited 43 and the other 148 eggs. Only one tick engorged and deposited the seventh time, 47 eggs being deposited. The largest number of eggs deposited by any individual during its entire life was 874, the average number of eggs deposited per tick by the individuals observed being 537. The tick which deposited the largest number of eggs engorged five times and deposited four lots of eggs. The number of eggs deposited by any individual seems, in most cases, to be directly in proportion to its size. The average number of eggs deposited by an individual after each engorgement, based on those that oviposited, is as follows: First, 131; second, 159; third, 133; fourth, 110; fifth, 97; sixth, 95; seventh, 47. In observations pre- viously recorded by Hunter and Hooker (1907) 274 eggs were deposited following a single engorgement. This record was based upon a tick which was adult when collected. The largest number of eggs deposited after a single engorgement by any individual observed by us was 237.
As is shown in Table IV, oviposition at summer temperatures may commence as soon as the third day after engorgement, or may be delayed for weeks if mating has not taken place. In the greater number of cases, however, it took place in from 4 to 10 days. Although _ the period of oviposition in one instance in which only a few eggs 21448°—Bull. 106—12-—4
“hid Pn 50 LIFE HISTORY OF NORTH AMERICAN TICKS.
were deposited lasted only three days, it usually continues during the summer months for from 6 to 10 days. After the fourth deposition, engorgement of the ticks became more difficult with each succeeding deposition. This seemed to be due largely to the weakened condition
of the ticks. It therefore appears that in nature ticks seldom engorge and deposit more than five times. It seems probable, however, : that if the first engorgement were made early in the spring and the ticks were engorged as soon as possible after deposition was com- plete, a greater number of annual depositions would occur and prob- j
ably the total number of depositions would be increased.
TaBLe 1V.—Oviposition of Argas miniatus.
First oviposition. Date nymph molted to adult. Date of first engorgement. Nie Dates. ber of eggs epee. OOS are eae cee eS ee oe June 212251908 55.2524: - 22 June 29-July 10, 1908......-- 125 PESTS: AGO Rte reels ein eae tea roan ie enese CS ROP Vea ies Sap a fa all ia iM wo June 28-July 7, 1908......... 134 3. Het oe 1908 boy See eee: July 31—Aug. 1,1908........- Aug. 28-Sept. 1, 1908........ 49 Ae aly LUG seenoce. eee ene July 27, 28, Gun team Didinot depositiass. = =e Eee Py UVa GUS eac ake Scene Foe a ee Jes eige GG). eanec a eke eh eoeee July 31-Aug. 8, 1908.......-. 135 Se Jilye 4, (ase i ie see ee eee July 29, 30, Wa0s. 252885 eee: Ate -3, HO see oy et eee 145 HMI; MOB te oe ci oe eee ee July 31-Aug. L 19082258252 Aug. 6-12, W908 seo =< eee 131 Bern yer, VOOR Me nee een See ee se Wulye27 2s lO0S a caceeseeeeee Did not deposit weestose ree dee ae OrdutlyO08 cate Cote ase ce ee ae pane GOs cea Sa 3| Aug: 6-9" 1908-29. oes ste 56 OSU Y UGOS ete keen ee eee Juiby: 29530) M908 hee ee Aug. 11- 13, W908 ae bose cer if He lived, WOOSe As ea < rat eer ee ena July 27, 28, NGOS Side ao etens Aug. 1-7, HOUR ceo, Oy reg 174 IE hy LOGOS oe ee coe eee Dil 29) SOs WONG e ec seer Aug. 28-Sept. Sp lO08 aces coe 101 MSE AIS 22) 1908 2 ue en Mee as oe cee ae July 31-Aug. 1, 1908......... AUP DLL G08. eee eae 127 TAS UGA LO LOUR eRe soe cence cee emer Septscl. 25 WOURse or ect ae Sept.v—lo; W085 ae eee 161 ee ANIo Sts 908 ose ele; Ae ae eee Alig: 27, 285 1908205252 oe Ae Sept. 2-8, 1908......... eee 8 195 NGS a GOR a ease ae ores roe Bans it | pate SUARE 3k Pyle Sept..2=9) 1908s ctascae eee 151 iia dune 15—Jiliy 15, 1908. 55. ns ee July 31l—Aug. 1, 1908......-... Sept. 9-15, 1908....4-. 22-2425 154 TS eEAUIS. Ls NON Gees con gai os eee Sept. 3, 4, 1908. AER Nee ears let Sept:'9-l6; 1908s Ss ese eee 151 LOR OB Beaks nth nce Ree | Aug. 27, 28, N90 82c eos ete He Sept..3-110) 190822... S252 se a23 144 Fe Meo LET i ett ates a Meee ge st Senta ey hs (Go aa einen Oe Shae Rh eS 1 | Sept aoe 1O08 262 see eee 176 pe me LOO) Se res iach hee ete eS (0 (0 ne ee A eres TR ee) PRO lle eR Oy ey a | 165 Second oviposition. Date nymph molted to adult. Date of second engorgement. Num- Dates. ber of eggs. AL eTuINe S908 Fe ee eA Bag eee ully?29;5'305 1908 ae Avg 8-13; 1908: see see e eee 81 2: June, OOS ee ae ee ere July 31-Aug. 1, 1908......... ANE o-U W908 22. sea eee eee 111 BY June-July, QOS r= es eee tee a 8 Sept. 3,4,,1908e = 3225 es Sept. 7-14, 1908............. 146 AEVETil ys. 1908 oro eee ee ee Asie 2122" W008 tees Sones Sepiat0-17) 190829... 15.2 83 DoLit 908 2 A eee ee ee soy Aug. 14, 15; A908 oe ee eeise Aven 827, 19082) ce eee eee 170 Gera G08 ee 2 Sere alee ae cote Reena ae oe WO eee cere eee AUIS S20) 1908 ae an a eeese 172 Teele: OAS, $5 4 el pees Ang 0U 22. BOOB 5. oe boa ee Aug. 27-Sept. 2, 1908.2. 9 154 Sry al LOO Se nena cee ae eee ee Aug. 25, 26, NGUS. se ahoseese Sept als, (908 he saan esses 156 Oey Tilly, O08 he ee acer see Meee Aap 145 5 1 GOSS 2 fy | Se Avig20—-28; 190852 ees oe 137 TK OSEU Bill ie L102 eee pe ean Rp ged at ANI. Dit 22 N90 Sees nes ce Aug. 28-Sept 5, 1908...-...- 137 Ue Oily. 7 LO08 534-2 shes see ee JANI LA 5 O08 se = See 3 Aig, U8=27 \ 1908-28 25s see 227 fo ely oi). Pole ee ee ee Soph. 7a lo0se ee ee Sent. 12-15, W90e-c eee 167 132 Apre22: 908s een eee eee IAT e AAS IDs 1908 se bese eee Alig. 17-28, 190855 Soke 163 PAS ANIS NS G08 coca a ete ae oe Septd4 tb O08 eeeec eae Sept. 20-Oct. 4, 1908........ 219 15: CART SUSt M908 io Sasessock ease eeee Septal d2 A908zees a: = = Sept. 16-24, 1908........-... 193 IC ae gl C00 eg at pee meg oe pl Dow Te 3 (6 Yas gs iealearh Seek Ca Sept. 15-22, 1908..-.---.-2-< 89 17. June 15— Ilys G0 8s eee eee Septe20; 21 908 seas a) eee Sept. 26-Oct. 14, 1908....... 195 1S. ANID CL]. AGUS eon tee eee eee ne DOr eee eee ne Sept. 25-Oct. 19, 1908......-. 237 19s 908 ee a cee ee Septy 143155 1908s shee Sept. 20-Oct. 3, 1908.-1 ; Sauee 181 A Fo BLOOD Bee eee cing eer nian eee Sept. fi, U2 MOOS Ce seen seers Oct. 8=22) 1908) sos ee neers 145 21. pf A908 aac en ee a Rael GO ested eee ee Sept. 16-94, 1908.05. caadeeae 182
THE FOWL TICK. 51 TaBLE 1V.—Oviposition of Argas miniatus—Continued. Third oviposition.
Date nymph molted to adult. Date of third engorgement. ested Dates. ber of
eggs. Herne, LOSS Sees. 28 see eit hak. Ae, LAS TOL GUS see dee ose Atle. Vi —2A, MOOS ax aa $oea te 5 111 ty Asia Tea be URES ae ees Seen a oe Le CS (Une OI, 8, ee Ie mt yee Aug. 18-26, 1908 02.2225 222% 163 3. June-JI UL. LOO Scere. Spa ae ees co 5 COs cya ee eee Sept. 20-27, 1908... 35558. 153 Ue, F008 oo on Cet dene ied Sept. 20,21, 1908.2 £ 22251. Sept. 25-Oct. 8, 1908........ 116 5) Gd UllicAit il 1 eee es Se Aug. 30, 31, 68 ee BOD ts U2, LOOB. Secure socks 172 Geriiy 4 VOOR: o.oo erie A eee 2S DOSS hice eos Sept. 4-10,1908........20.2.: 160 Tey 1908 5...) Sdneetee=, See Sa SAS) 0) Fe eo (ces ee a Sept;.7~14,.1908. oc ccc seb. x 243 ULV i LOOSsee sso 2 cited et. dace Sept. 27, bs, LOUB its ioe Oct Waalor lobe aeons ss 76 1) 0A 0 Grd (10S tae a atecek Peas een ee ce CE (AQIP BO OL gOO Bane coe arc iete- Sept: 714, 1908. cesses > a 139 Uke GOK AY GS eee cena ae ee SOD las. 6, lo Ste wc etme eas Sepia 15,1908... 122 Mie WU 70908)... < o.355).5.- rate see pea ATI Es SO ol, LOO Sider eiee aoe ae Sept.:3—-11,, 1908. asec s ss: 245 12. July 410, LOOSE. thew 88 wy: eee Sept. 21.22; 19082 2. oes. Sept. 26-Oct. 8, 1908........ 177 13; Apr. 22, LOG. 5 Sestivmnnciayes £5.57: Ae ASO; dle MOOS saa tecece os Sept; 5-11 1908250550 225-2 50 14. Aug. 15, 1608. 5. eee oe ee oe Oct: 5; 6, HOM eet atu Oct. 15=Nov..9, 19085223 2. 2-- 227 PEPPATIS UIST NOUS cio. 6 x eles lay doit seca Sept. 28, 29 TOUR Fetes eee Feb. 19-March, 1909. ........ 118 ee LOS ipwd- Sel iivemee ee AO erord ohetieutecmea ote: Oct AL TONS iia ase ee 4 17 June to—-Tuly-15, V908isa0 2552555. - Oct. 27, 285 LOS s cere pec tee Nov. 14?-Dec. 11, 1908....... 149 Pe TOUR ener ti Cee! do...) oul ase bate Did not depositucts.2.5"-.-tlese see 19. ——, 1 RSS Cate ne aie Oct. 5, Gy LO0Steeeeec cea Mar. 15-Apr. 5, 1909.......-.. 102 i LONG. SS TONE ek eS Oct. 29, 30, GO Sum atl ee Maire 2-2i nt G00 cA 5 ue acto = 8 25 Pee MOOR nd = one oes ciceiora eo Sensis Sept. 27, RGN so Oct: 6-205 19085 3 ate oe 106
Fourth oviposition.
Date nymph molted to adult. Date of fourth engorgement. ane Dates. ber of
eggs HMO; 1908 52 5 eas See SEAS hie 30, SL, TOOS..5. 22. 2S. Sept. 8=15, 1908... 2522225. 97 MTT: MODS cc Pees A as ae NS: Sept, i, 2) clOOs ee oe. STE) Tey Ea is fee Io ee a 126 Ree Iuly, L908: Sree seks 385. OCE G28, 1908 Ese ee. Feb. 23-Mar. 20, 1909........ 90 ey. L908. ok ees Ost Se Se kT OCl 21, 28S LOOR Meee cae ene Hebi:2=23, 1909 cc ee ee 72 PPMMMULLYe dig al QOS crc) ojard sare’ rerm cicvopneiaeistaie Sept, a4, U5, 1908 3. see cerns Sept. 20—Oct. 5, 1908........ 82 mnnly 451908... eb... eeeds Sed. Soyo ey at Paes 7.2 ef ee ee Eee Sept. 7-25, 1908. 555 e2s0e 167 MUIR OOS Se i. 4 otis else eat Sept. 21, 22-1908. 0. 2-< .~< Sept. 27—Oct. 17, 1908....... 182 merle, VOOR= o . S Gee oes, see Did not engorge es ee AeA: |: | ee Ne Oe eee kay ee PMU A OOS 5. carete 5. loa, aoe Sept. 14,15, L908s55. 2225526 Sept. 18-Oct. 6, 1908........ 81 MLL G08 Seis 2 ck cic coo skate Sept. 28, 29) HOUR. Weems oe Oct. 8-22; 0908 = osc 114 In, Letty aay (ga M0) eS ee ea Nepean Uo TOUS lc occas ot Sept. 19- 30, 1 eee eee 228 ipacly AO) 19083522 5..5- 2.22 .lee. Oet Zigee Louse cciene oe See Feb. 21-Mar. 619095 oe oe 7 PAPI 2 LOR. co 6- cene no dacn PE OESED bapa Woy LOU Sie cats.ce cm cats Sept. 19, 20, WANS 8. ese 11 [LUANG BRS 0) IDEC Oy Oy kGUS. so cccccce las ~ Didinot deposits... scan fe PPA SUST 1908 5 cic.c 008 a cecsec cess Do ea Co LY Pe eo ee ae Apr. 26-May 9, 1909......... 176 Vay SSS Sp eee eee Octr 27,428,908 secaee. oon Did not deposit i ee meee gat he) [kage ties d 18. Aug. Rip MLOUSe Seat tats cose wate s S- June 8, 9, HOG go ce iiedhtdine! 205 1909) oS. os secs ache 19. —, ee me oe Apr. 16, i7, UD deee ese acacia Apr. 24-May D4, TONGS e. 205.2 60 20 eal eee ete ae Pee eee June 8, ’9, RONG Sat) Did HoOb-Genosit 4. tu Ace ee Pe LUG. « Awe eth s ee ccccm ee Oct. 28, Se 008, 0... co, Feb. 2-Mar. 8, 1909.......... 97
59 LIFE HISTORY OF NORTH AMERICAN TICKS.
TaBLe [V.—Oviposition of Argas miniatus—Continued.
Tifth oviposition.
Date nymph molted to adult. Date of fifth engorgement. ieee Dates. ber of eggs ee ume y L908. cate ere heen Sept. 205-215 1908 see cee eee Sept. 25-Oct. 17, 1908......- 135 PsN bas WOK) sane me Pere istcite is, eR Pe ASey oN TEC ay ICO SE Se ee Sept. 23-Oct. 17, 1908....:.: 61 So) June ally, O08 ae eee tere ADE22, (235 G09 Eo eee eas May 11-16, 1909 2.22.22 .2 22. 72 i Ax DULY, AGO 8 Ree a ahee a Re Avr dG. 17 OOO. Seca sate bene May 5-14, 1909s eee Soeeee 85 a Os July AQOBL: nee ee ea OCB LT, 285 NOOBS cre Rees LONE BR Sy oe ose a ag a ee i Go) Dull yi: 1908. ke eine he Aes a Sept 278, Fone. Sam Alar yo OOO. sconce 1 @ hse Duilye, L908 an oc eee een OCts 27, 28, 1908ee a nee Didnot deposit. == 26s \aeeaee : S21 Sy 1908 ses Sek Se io eee Did not engorge=e4= es aceeee Crushed :Atpr.)245 19092a ees eee 4 Oe Suliy PING a sae eee een ae OCE 27528, MOORE Sree eae Did motideposit.ees]- eee pee rs LOS uly 1O08.: 5. SOA tees eee cae do. Cees: ne TiOStha nc oc Sock trate ahaa Oe Le ULV i NOOR ie 2 ebe eos aa ieee Did: nobtiengoree = ase aseees eo aese ee ec senna ee eee ae y Lec Sully, 41090 Rae sees ae are Apr iG ili mO09). ska aoe Apr. 24-May 14, 1909.......- 155 f eh ACT: 22) OO R=: Sane A ee i ame OctsG:4 AS0SEe cee see oeeee DidmotGeposit sess eee eee | dee PAI es 5 OOS eee ee eee ane eee June Wael Sd G09R sae see JUNE 21270 kee ee eee 114 16. OO Beso SEY ae Fee” Sea ae E25 20 MOOI see ae eee | oni ticyave tei ceta/are feline sedate al ' 19h ANDG eS see ae Sip A 95 GHGs os amet Aug. 20-Sept. 4, 1909........ 201 . 20 =——" 1908). Sask ee ee Se Oct: 285,20. USNOe cme ee eee Did moti deposit-252 2s 4-sse0 epee a 2) ae eer eae hee EC Es Oe 3 Sept: 16.07, 100s. 1. ae Apr. 28-May 12, 1909........ 41 i aye , aa : & Sixth oviposition. ‘ Date nymph molted to adult. Date of sixth engorgement. Nuns : Dates. ber of eggs i DMRMIATIO NODS eee ern ae EE OCtH27T A 28 IGOR Ae see eee Died uly V3 9095 58. eee i Sey une aly (G08. oe ee eee Did not engorge............- Diediiualy V5) W909. oe eee ee x Nate je Ln ih Ste eit SA aS Sh OTN Ny AE Diediulyit3; 1909.02 ee eee Bs ea Ulys rept O08 a eR a en OCt/28;)29 1908. Et eee Killed) Dec.-5, 908. 2 eal nee i Gag dullyo4 G08). aaa: eh 8 eee Didimotenrorseness. cece Diedsuned3; 1909 22 eee cel eeeeee ft Re DULY BIOS ys eater Pee ears ee ale Nov. 19,20 1o0R: eee eee Did mot deposit <4 2.2553 6.5 pea eae ; deleerIublived, T9082 eee | eee | Did not engorge, Oct. 27, 28, | Died Nov. 21, 1908..........|...--.- ri 1908. ; Ae Aneel 5) LOOR =. subtree eet ke EE emer Sv oe Bred) Me ia i Died Awg.:23,) 1909). she. S| eee HG ny IOUS ee Waa 8. at eee Pe a Peete ee ee Bg RN ee, Died) Keb.:20: 1910) 7 24s eee a 1G) AEA 1) Spl ea eae ei iin eas Cis Septi20/ 21, 1000s 1s: es Lie Oct, 925.1900... 2-5. eee 43 ; ZAR ——— S1GOR OS. Meine Ba IOS ie ea ee| ANI 625 265 O09) eee ae eee Aug. ?=Sept: 6, 1909... 22-2 2-2 148 * Seventh oviposition. Total. Date nymph molted Date of seventh engorge- Num- Mine to adult. ment, or death of tick. Num- } ber of ber of Num- Dates. berof| en- |g eposi- ber of ' eggs. | gorge- | 4; eggs ments. ions Se OUITIO O08 sere eet Digdi OCt!28 M08 ieece:52 a4. | aes ee eel Rage 5 5 549 Me Avia sss Seen ee Died: Duly ds 1909... 2 as cela eses oe eee eet eee 6 5 595 > 3. June-July, 1908... -- Died Suuliy7l5; TO09 meee ata |Gaace Seer ee ees ieee 5 5 510 ‘ AS DULY OU Se eo ceeenee Died Jubky U3, 1909s. aes = celeow eee sees nee ee 5 4 306 DemUlyetn O08 ease eae Kalled Deeb) (O08 a0 2 Cee Oke ee eee 2c eee 6 4 559 Oy Uli Sale eee sese Died ume ls , GOS: sore ae se ea spre acer 5 5 655 Te Abby al 03S os Be ee Died? Dees VO; MOOG ee see oe hoe eye co i are 6 4 710 Sa ULV GOS severe Crushed Apr. 24 GQ O9n) mesh sors 15 SNe alee Nan |p ae iar 5 2 252 Oo dully, D908 e255 Lost) JUNE AO: AGO Gs tet Less he ee ey ete cee eye eens Selear 5 4 413 LO bya GSE ee ee TOS Gee Se See eos et REN SP er op | a ns 5 4 380 10 dibibyi 7 UMS. oe eons - DPE IN Oven 2 fa OS is eee aL ag cp ae Be 5 4 874 12. July 4-10, 1908.....- Died: before Aue: 4. T9092 OS 2s eo Se ae ees 5 5 672 13 Apra22, LOS: a5) Died: ually WSs TOMO es aretha Ree [Pee | 5 4 351 LACS Atttezalo O08 n= occ Died Aig S 23 1 Q09r Ree aes 2 Sree cera aye eres | ee ears 5 4 721 lbs -Awousts l908 Ss. a= - 52 — Disa aliyslG909E Sa oe = 84 Geer reee seer Sees eo aseeee +f 4]. 682 16. MOUS ec reso Peete Died Meb.QO9i0 ss. 2s. Sa Ue eee hae open 5 3 244 17. June 15-July 15,1908} Died Jan. 5, 1909..... cig eRe en gerne Le 3 2 498 1S Arete G0 Seema ee Died TaMM| 20s MOO = see Ree a a sae ee 4 2 388 19. QOS Pee eee ope Mar.(85:9) 1 GI02 eae eae Did not deposit!_|......-. uf 6 731 20. ——, 1908... 22 - sail) Died Mar.30) 1910 ie lao sees eee eee acer ae 5 3 346 2 ——— L908 oss Seen oe Sepia 20 2 900s eeee sae Oct. 2-8, 1909 2... 47 a Tf 786 1 Died Apr. 4, 1910. 2 Died Dec. 10, 1909.
j |
i
. ;
THE FOWL TICK. 53
The period required for the incubation of eggs in August was found to be as short as 10 days, at least 437° F. of effective tempera- ture being required for incubation. Eggs kept in an incubator at a mean temperature of 89.8° F. hatched on the ninth day, an effec- tive temperature of 421° F. accumulating. Rohr states that eggs kept at 35° C. (95° F.) hatch in from 8 to 11 days.
TaBLe V.—Incubation period of Argas miniatus.
Temperature during incubation.
| | Minimurh Eggs deposited. | Hatching. a Average | ony | | Maximum. | Minimum. — eilectber: Days. “FF, mae a. | F, Tune i | Tuy 11, 1908...-.-.-. | 13 93.5 70.5] $1.44] 499.75 uly 1, 1908.........-..| July 14, 1908......... 14 93.5 70.5| 81.98] 545.75 July 9; 1908.......-----| July 4." So 13 94.0 74.0| 83.79 | 530.25 July 31, 1908.......... Aug. 12, 1908........ 13 99.0 73.0| 86.15] 561.00 Aug. 5, 1908........-.- | Aug. 15, 1908.......- 11 99.0 73.0| 86.59} 479.50 emt ees oes | Aug. 16, 1008..-..-.. 10 99.0 73.0| 86.75| 437.50 Re is 1508.2 | Aue. 30, 190822222 13 93.0 7a3| ss48| 526.95 Aug. 24” 1908.....1.12_| Sept. 5,'1908...02.2) 13 94.5 75.0| 83.40| 525.35 Aug. 31, 1908......._.- Sept. 11, 1908.......- | 12 | 7.5 74.5 | 84.41 | 496.95 oe ee Sf ieee eel ee “eS Sk, See soe ifs 9. i> / i200.
ee Nov. meee: 40 7.0 -34.0| 65.20] — 887.00 Se | Nov. 7, 1908........- 31 7.0 45.0} 67.00| 743.00 Nov. 7, 1908.......-._- | Jan. 22, 1909....22.2. | 77 82.0 17.0 59.50 | 1,141.00+ Nov. 9, 1908........._. Feb. 23, 1909.......- 107 85.0 17.0} 59.50 | 1,582. 00+ Nov. 23, 1908.........- Rat ae eee | 93 85.0 17.0| 58.50} 1,339.00+ May Tee | May 20, 1900-2. 20 95.0 51.0] 76.50 | 671.00
pt. 20, 1909.......... et. 15, 1909.......-- 95.0 52.0) 74.50] 860. fet. 2, 1909-2 2 Oct. 24, 1909 | 23 94.0 52.0] 73.10] 693.00 Oct. 6, 1909............ Nov. 3, 1909.......-- 29 92.0 51.0 71.60} $31.00
The larva (Tables VI, VII, VIIT).—Seed ticks kept in pill boxes in the laboratory at an average daily mean temperature of 61.9° F. have been found to live as long as 164‘days. During midsummer the longevity is about two months.
TaBLE V1.—Larval longevity of Argas miniatus.
Days | Days
Date hatching Date all larve from | Date hatching Date all larve from began. dead. hatching | began. dead. hatching to death. | to death. mr 9, 1908.....-..| Oct: 20, 1908... ...: G3:.| Now: 3; 1908.62: .225 Mar. 22, 1909. ..... 140 Sept. 8, i | eens Dec. 25, 1908... ... 108 | Nov. 9, 1908.......... | Mar. 27, 1909.....- 137 Sept. 25, 1908. ..... Jan. 24, 1909....... 19) ) Dees A008 eo 2: | Mar. 17, 1909...... 105 Oct. 15, 1908. .....- Feb. 24, 1909...... 132 | May 18, 1909.......... July 15,1909... .-. 77 Oct. 17, 1908....... Mar. 30, 1909... ... 164 | May 24, 1909.......... | July 27, 1909...) 64
ore. 21, 1908. .=.-. Mar. 27, 1909.....- 147
At a temperature varying from 18° C. (64.4° F.) to 27° C. (80.6° F.) Rohr has found individual larve to live as long as 65 days.
Ordinarily larve do not commence to drop from the host until the fourth day following attachment, although one may occasionally leave the host a day sooner. All the larve which we observed engorged
54 LIFE HISTORY OF NORTH AMERICAN TICKS.
and left the host by the tenth day following attachment. The obser- vations of Rohr (1909) on the dropping of the larve do not agree exactly with ours. According to his records in Brazil the larvee may commence to drop as soon as the second day following attachment, the greater number leaving the host on the third and fourth days and all leaving the host before the eighth day.
TaBLE VII.—Engorgement of larve of Argas miniatus.
Number of larvee dropped engorged—days follow- ing attachment.! Total
: : e number Date larvee were applied. es Be teal ioe re [ot aga ie ean (MR) ia | REC INTs OA IED 7a OV Oy pgs 1 emer ete Res eb 0 OF Ptr le 4 1 0 0 34 Mie AOo1G07 5000 pean. 2 ets ae LE 0 1 9 6 4 1 0 0 21 Octoils, 1907, Ml 00 a samss ee a oe eee eee ae 0 0 0 if 1 0 0 0 2 FUME SG. 1908 BOps Wiss sans os cee ee 0 0 Oo! 48h. ot 2 0 0 64 Ae e227 L908 O00 ip. Wises. sos soe ee Ie 0 0 18 12 2 0 0 0 32 Sept. 20; 1909;10.30 p.m. Jess: ocd. ce eee eee £10036.) De aah Sa 5 2 1 95 Eo eR rot ie RRP eet emcee een) nro 0 LG 4 3 3 0 0 0 1h Oct 2251909 10.00 ip amces ons so cette ee 0 0 0 12 17 10 9 2 50
1 Tn this and all subsequent tables in which this arrangement is followed, the top line of figures represents the number of days following attachment or dropping and the figures in the columns beneath represent the number of ticks dropped, the number molted, or the number of eggs deposited on the respective days following attachment or dropping as the case may be.
In a test to determine the relative susceptibility of individual fowls to tick attack, a Leghorn pullet, a Barred Plymouth Rock pullet, a setting hen (part Leghorn) and a sick hen (part Leghorn) were placed in a cage and infested with larve. An effort was made to place about the same number of larvee on each individual and a number were left free in the cage with the fowls. The following number of ticks dropped from the different individuals: Leghorn pullet 26, Plymouth Rock pullet 27, setting hen 95, and sick hen 13. The sick hen died on the sixth day after infestation. A second infestation of the three remaining fowls was made on a later date. At this time the setting hen was no longer inclined to set. As a result of this infestation, about the same number of larve were engorged on each of the three fowls. The experiment tends to indicate that there is no marked variation in the susceptibility of individuals of different breeds. It appears to show, however, that on setting hens, which are quiet at the time of infestation and after- wards, the number of larvee which develop is greatly increased.
Up to within a few hours of dropping, the larve are globular in shape, but at this time they flatten and assume the typical Argas shape, which permits the tick to crawl rapidly and secrete itself before being discovered and devoured by its natural enemies. Barr- ing accident the engorged larve drop only at night when their host is upon the roost. The larval is the only stage in which the species remains upon the host for any length of time. Advantage can be taken of this fact in preventing its dissemination.
THE FOWL TICK. 55
Seed ticks have been observed to gather on the ventral surface of adult ticks and it is thought possible that they are at times assisted in finding hosts by clinging to the older ones.
In August at a mean temperature of 83° F. molting commenced as soon as the fourth day, an effective temperature of 160° F. being required. In one case a molting period of 32 days was observed. In this instance the individual was undoubtedly very weak as it did not succeed in freeing itself from the exuvium without assistance. Rohr states that with a temperature of 35° C. (95° F.) molting takes place in 4 or 5 days.
TaBLeE VIII.—Molting of larvx (first ecdysis) of Argas miniatus.
Temperature from Larve molted—days following dropping. dropping to date first tick molted.
Dateengorged larve |Num- droppei—night of. | ber.
|
Num-
| - . | Average
2 ber | Maxi- Mini- aa SP
415] 6] 7) 8] 9 | 10) 11] 12] 13} 14] 16] 17] 32] ee ae eam | daily
ed. mean,
| ; | | oF | <¥ °F Aug. 16,17,1907...-| 14|0|10;1/0;O0]0}/1/0/ojo;/o];o/ojo] 12]......)...... eee ee Aug. 17,18,1907....| 1010/5/3}/0/0/0/o0!/o]olo}o]0| ojo a ae ae Sener bs ng et lee Aug. 18, 19, 1907... 4) 1 0/1/0)/1/0/0/0]/o0]/o0]}o0]o0]o0]0 9 om Baty. san Aug. 23,24,1907....| 9/0/2/4/2/0]/0 0| 0 Oo}o}o0}]0|0]0 Se Eee Nery eo Aug. 24, 25,1907.-..| 6/0/3/0/0!/0/0|\o0;0/ol|o/o]ojoljo A RBM ahd) eer Oct. 19, 20,1907....| 1/0]/0/0]0]0 0/0| 0 0\0;0}1/0]0 | RR Nira, RIES) « 5 4 Apr. 23, 24,1908....| 2/0}/0/0]/0/oj0|o0;o0/1/o0]1]}o0]o]0 2 | 83.0 | 47.0 67.90 July 5, 6, 1908.....- 48\0|31/5/4]1 0/ 2/0 0/o0/o0|0]o0]}o0] 43] 93.0 | 75.5 83. 00 July 6, 7,1908...---| 14/1/8/3]/0/0/0|/0;0/0]/o0|/0|0|/o]o0] 12] 93.0| 75.5 83. 00 July 7,8, 1908......} 2}/0]/1|/0]0 0/1! 0/0 o}olololo}o 21 93.5 | 75.5 83.79 Aug. 26, 27,1908....| 16}/0}4/3/4/0|/o0/o0;o0/o/o/]o/o]o]o]| 11] 89.5] 75.5 83. 29 Aug. 27,28,1908....| 12/0]11;}1/0/0/o0/o;o0];o;o};o}o|o|o| 12] 89.5 | 75.5 83. 29 Aug. 28, 29,1908....| 2/0}/1/o/o/o/1lololo/o|o|olo|o 21 89.5 | 75.5 83. 42 Sept. 24, 25,1909....| 70/0/0/0/0|3 (36 lo} 1/0|/0/0/0/0]0] 50] 91.0] 56.0 72.9 Sept. 25, 26,1909....| 33!10!0/0!0]8119/3!0]0!0}0!0]0!0] 30] 92.0) 56.0 73.7 Sept. 26,27,1909....| 28/0/0 0| 3 4/1 Abe 0/0}0]0]0/1] 23} 92.0] 56.0 74.2. Sept. 27, 28,1909....| 201/0/0/4/12}4/o0/o0]}0/0|/0/0/0/0/0] 20] 92.0] 56.0 75.0 Oct. 27, 28, 1909..... 37/0|0/0/0]/0/0(112)141710/2]/0/0/0] 35] 84.5] 55.0 72.5 Oct. 28, 29, 1909... .. 32/0/0/0/0/0! 3/14 lo}0/0/0}/0|2]/0] 29] 84.0] 55.0 71.8 Oct. 29, 30, 1909. 10/0/0/0}0}/0/0|5])0]3}/2]/0]0]|0}0]} 10] 84.0} 55.0 71.7
Powe! & =o! 370 | vfeeleefee cee
The nymph (Table [X).—Rohr shows that at a mean tempera- ture of 15° C. (59° F.) first and second stage nymphs may live as long as two years, while at a temperature varying from 17° C. (62.6° F.) to 33° C. (91.4° F.) all under observation were dead in 469 days.
This species appears to vary in the number of molts that it passes asanymph. As previously shown by Hooker (1909), there is a third nymphal molt in many of the individuals which have been reared. In view of the fact that the extra molt could not be traced to a difference in the sexes, the food supply, or the climatic conditions, it is thought that it might have been due to an adaptation that the species is undergoing, as the fourth ecdysis requires an extra engorge- ment before reproduction can commence. The nymphs, like the adults, require only a comparatively few minutes for engorgement.
56 LIFE HISTORY OF NORTH AMERICAN TICKS.
Nuttall and Warburton found that two-thirds of the nymphs and adults engorged within 30 minutes. In observations of 148 nymphs these workers found 120 minutes to be the longest period required for engorgement.
First-stage nymph (Table [X).—The longevity of first-stage nymphs was found in one instance to be as great as 269 days. Of 29 first-stage nymphs, which molted between July 28 and 31, 1907, and were kept in pill boxes, 14 were found to be alive on October 12, 5 having escaped and 12 being dead. Of the 14 remaining alive 3 escaped, the others succumbing as follows: Two on November 14, 1 on November 21, 1 on January 1, 1 on February 18, 3 between March 27 and April 16, and the last one on April 25, 1908. A large number of first-stage nymphs which molted from larve October 3-8, 1909, were all dead by April 22, 1910, thus living slightly over 6 months. The greatest longevity recorded in a lot of 88 first-stage nymphs which molted from larve November 7-12, 1909, was slightly over 9 months.
TasLE No. IX.—Molting of nymphal stages of Argas miniatus.
[f=Male. 9=Female. @=Nymph.] MOLTING OF FIRST STAGE (SECOND ECDYSIS).
Temperature
First-stage nymphs molted—days following dropping (engorge- | from dropping
ment). to date first tick
ake molted. first-stage aes
nymphs : Num- Aver-
or 718| 9 |10|11| 12/13} 14/15] 16|17| 20] 23} 24] 25/26] 28] Per )Maxi-| Mini) age
A mee molt- |mum.|/mum.] daily
ed. mean.
ont es ee hs 27
Aug. 28, 29, 11SEC OY | 28 fae aca EM ALCO COS COA COSTS O MIMO I COON ) pele) ALI tees ee He 1907s ooo septs. 1 22:
LOD Fees: ss 10) |) .0)). 2:4 L 2a | 34-0) | O10) | (0) })0))) 0) 0) 0) 10) 10))|, 0 OW Bee eS eee Apr. 23,° 24,
OOS eis Sakae POT OO OO OHO NEO ORO Per at I IT eZee a 11 | 86.0 | 47.0] 69.3
May 20, 21, f
S082 ee | ee ON} OF ONO} 24. |) 4s) Se sOn0: | OnlKO nO 18 | 86.0 | 68.0] 77.5 Huly; 205-21;
O08 5 cs 2 37 (18 [13 |}0)}4/0;/1/0/0)/0/0/1)/0)/0)/0)/0)0)0 37 | 95.0 | 76.5 | 84.6
MOLTING OF SECOND STAGE (THIRD ECDYSIS)
Second-stage nymphs molted—days following dropping (engorgement). Date second-stage |Num-
Lhagh Teapot IEF 11 | 12} 13 | 14] 15 | 16] 17 | 18 | 19 | 20 | 24 | 26 | 30] 33 | 36 | 37 | 43 Oct. 3,4, 1907....-.-.-- gio 0°10 | FO. [ole | 0 hor lone Lo 0 lo Jo Jo Apr. 24,25, 1908......-- feos? 0 |o Jo Jo }0 0 jo Jo lo Jo Jo 19 {1g Me ig|1 |2¢ July 31, Aug. 1,1908....|......] 3¢ ig Bo do hho 1910 |o |o |o J1ieio Jo Jo Jo Jo Jo Aug. 4,5,1908.........- ]o Jo |3@is! 73] 73] 1S Lol Ls}o fo jo |o Jo |o Jo Jo Aug. 6,7, 1908........-- 7/0 Jo Jo Jo J1i@x{igflra]o Jo |1a}o Jo }o Jo Jo Jo Jo
THE FOWL TICK. 57
Taste No. IX.—Molting of nymphal stages of Argas miniatus—Continued. MOLTING OF SECOND STAGE (THIRD ECDYSIS)—Continued.
| Temperature from drop- ping to date first tick molted.
Second-stage nymphs molted—days following dropping (engorgement ys
Date second-stage nymphs |MNum-
engorged. ber.
177|183|184|185|195|199| Number | Maxi | Mini | Ayeuee
i/| 18: $5 oji SFC re (pare daily
/ molied. | mum. mum. migan,
= i ae ae a ee ied We ase 4
hehe te ae 7. SSS ee Piha eel se tones OP ae et een no + <p 2 ab oe owe Mee BE Pa 1903 e352 CeO) Ors PO COs HOE eh 87.0 | 47.0 70.91 July 31, Aug. TS DOS sie ws wis oa loco op 0 0 ;0 |0 0] 8¢)109; 05 99.0] 73.0 86. 06 me. 4,0) 1008. 3.2 8. tes 18/0 }0 |0 |0 |0 0/5¢, 82 4B 99.0 73.0 | 86. 61 Sp area 710 10 |0 |0 /0 | 0456}19) 1B) 99.0] 73.0] 86. 64
Temperature from drop- ping to date first tick
oe Third-stage nymphs molted—days fol- | molted. |
lowing dropping (engorgement).
Date third-stage nymphs Num-
engorged. ber. natty 4
ps avi. | Min; | Average
a Ec Hk Sag Mea ee ret
hed. ’ “| mean.
PE Sie Tay eae Abies Genes CATA ge
Vee Ole ee 2 “FF Bene 20, 9t,1008_ 2.2 -.-.-- 2 0 ative 29 2} 89.5] 71.0] - 80.73 ine. 28, 29,1908. ..........- 5 19 1g 29 | 19 5| 97.5] 75.0 | 83.98
Observations are recorded by Nuttall and Warburton, who found all of 14 first-stage nymphs of this species to engorge and drop within 35 minutes.
Second-stage nymph (Table IX).—In our experiments second- stage nymphs lived longer than those in the first stage. Of two which molted July 31, 1907, and were kept in a pill box, one died July 30, 1908. One nymph which molted from the first stage on June 15, 1908, was still alive February 23, 1909, when it was lost, thus having a longevity of at least 253 days. The last individual of a large number of first-stage nymphs which molted to this stage October 24-31, 1909, died January 12, 1911, thus showing a longevity of 445 days. The last tick of a lot of 12 which molted from the first stage November 1, 1909, died March 25, 1911, having lived 509 days, or about 1 year and 5 months. At a mean temperature of 86° F. in August, nymphs of the second stage molted as soon as the eleventh day following engorgement, 473° F. of effective tem- perature being required.
Third-stage nymph (Table IX).—We have found that about one- seventh of the individuals reared under similar conditions pass a third nymphal molt—i. e., of 49 individuals reared from seed ticks to adults 7 passed a third nymphal molt. Six of these after molting proved to be females and one a male.
58 LIFE HISTORY OF NORTH AMERICAN TICKS.
In August, at a mean temperature of 84° F., molting commenced as soon as the ninth day following dropping, an effective temperature of 369° EF. being required.
The adult' (Table X).—The males and females may be readily dis- tinguished by the shape of tle genital orifice, that of the former being crescent shaped while in the latter it is merely a transverse slit.
The longevity of the adults is surprisingly great. From a lot of ticks collected March 24, 1906, which were kept confined in a vial with a cork stopper, one lived until September 3, 1907, a period of 17 months. In two miscellaneous lots of some 50 or more ticks collected May 12, 1906, and kept in large vials with paper strips, the last individual died about October 12, 1908, having lived for 2 years and 5 months. Some individuals in nearly all of a large number of lots of collected ticks have been found to live more than one year.
Females lived from 5 to 13 months when engorged soon after they had molted to the adult stage and immediately after each deposition. One specimen, which was engorged three times, lived 18 months, depositing 244 eggs in the meantime.
The longevity of adults which have not fed after molting appears to be slightly less than when some food has been taken. One in- dividual, which molted to an adult August 16, 1908, was still alive May 27, 1910, having lived over 214 months. However, most of the specimens observed died between 4 and 12 months after molting. Laboulbéne (1881) has reported the fowl tick to live (unfed) for more than three years.
Fertilization is accomplished by means of a spermatophore, which is deposited by the male at the genital aperture of the female, follow- ing the introduction of the hypostome of the male into the genital opening of the female. The act of copulation is described in some- what greater detail on page 30.
The adults engorge repeatedly and oviposition follows each engorze- ment, with few exceptions. Thus, as shown in Table IV, we have found females to engorge as many as seven times, each engorgement being followed by the deposition of eggs. Lounsbury (1903a) has found females to engorge as many as seven times and to deposit fol- lowing six engorgements. As has been stated, Nuttall and Warburton found that two-thirds of the nymphs and adults engorge within 30 minutes. We have not determined the exact time required for engorgement. However, in one case 38 per cent of a large number of adults applied to a fowl had dropped engorged when examination was made an hour and a half later. Usually engorgement takes place at night, but when fowls are exposed to their attack im dark
THE FOWL TICK. 59
places, such as on nests, engorgement may take place during the daytime. In warm weather oviposition is usually completed in from 10 to 14 days and engorgement takes place again as soon as a host is found.
The dimensions of females prior to engorgement is increased slightly with each deposition. The average size of an individual taken after successive engorgements does not, however, seem to increase noticeably after the tick has become replete the second time. The size of males also appears to increase slightly with successive engorgements. The maximum, minimum, and average length, width, and thickness of eal) the He entities of which is recorded in Table IV, before and after each engorgement, is given in Table X.
TaBLE X.—Size of females of Argas miniatus before and after successive engorgements.
Number Size before engorging. Number of engorge- | of ticks ment. meas- ured. Maximum. Minimum. Average. Mm Mm. Min [ONS See ee Oi T- DY Bre 252 25-52 5h. = a eee ee 6.4 by 4.1. a ere ee $1} 5.5 byaeiiitt-i e- ey oe ee ee 7.1 by 4.4 lh ae ee «fej WRC 6 al ee a TATA Ee. eee = See 7.4 by 4.5. UTE ae eee 1 3198) Dyn tis ae be > Giepyi4ase ss . 552 por 7.5 by 4.6. 2 Lib A ees 14, 8:8: DY 5:5 DY 16222 ~ =: 6:3 by 42°py 1.3_..-~ - 7.7 by 4.8 by 1.5. CE 8'| 9.6. by5.9 by. 2.3.:.2-%- 7 by 4.3 by 1.2.... 8.1 by 4.9 by 1.7. ESTE ee ae 2 Sa DY el yore ee: PADDY OL Dy l.3>. 2252: 8 by 5.1 by 1.7. Number Size after engorging. Number of engorge | of ticks ment. meas- ured. Maximum. Minimum. | Average. Mm. Mm. Mm. ee ano by Giby?3:5: 2" ta. Gilby 4 be See Freee 8.8 by 5.4 by 2.7. ae 20 | 10.5 by 6.5 by 3.5...... Shy & by2.5..:..-..-- 9.5 by 5.6 by 2.9. eee ee ef PAR DyiGsbg3.5 2 So i2s. 8 by 4.2 by 2.25 9.6 by 5.6 by 2.7. hee 17 | 11 by 6.5 by 3......... 8.5 by 4.5... .| 9.4 by 5.5 by 2.6. re ee 2 See 3 14 | 10.3 by 6 by 2.7........| 8 by 4.7 by 1.9....-.-.. 9.2 by 5.5 by 2.5. a £4102 Dy.05. Dyv0-... 4-4-|.9-4 Dy 5.7 DY 2.4... 9.8 by 5.9 by 2.9. SG 2 | 9.9 by 5.9 by PSG) Si $.3'by 5:5 Dy 332. 9.6 by 5.7 by 2.8. LIFE CYCLE.
This tick as a larva attaches to a fowl, preferably beneath the wings, remains attached usually for 5 or 6 days, becomes engorged, and, afew hours before dropping, flattens out and assumes the typical Argas shape. The larve drop at night, at a time when the fowl host is upon the roost and where they will be near the host when ready to engorge again. In summer a period of 4 or more days passes before the engorged larve molt and the 8-legged nymphs appear. The second engorgement, which occurs at night, lasts only a few hours at the most and is followed in summer by a period of 7 days or more before the second molt. A third engorgement occurs at night and 11 days or more pass before any of the ticks molt and appear as adults. In about one-seventh of the individuals there is an extra nymphal or
60 LIFE HISTORY OF NORTH AMERICAN TICKS.
fourth molt before arriving at the adult stage, 9 or more days (869° F. of effective temperature) being required for the ecdysis. The first — adult engorgement then takes place, and following copulation eggs are deposited. Unlike the ticks of other genera, with the exception of some species of Ornithodoros, these ticks engorge a number of times as adults, and each engorgement is usually followed by ovi- position. The eggs may hatch in summer as soon as 10 days, 437° F. of effective temperature being required for their incubation.
ECONOMIC IMPORTANCE.
In parts of the southern United States this tick 1s the most impor- tant ectoparasite of fowls, though perhaps surpassed in some locali- ties by some of the insect pests. It is frequently referred to as the ‘blue bug”’ because of the bluish color when engorged with blood. In Brazil, Martinique, India, Soudan, Transcaucasia, and South Australia a disease of fowls known as spirochetosis is transmitted by this species. The presence of this disease in the United States has not been demonstrated, but on account of the losses due to the tick as a parasite in certain sections of Texas, poultry raisers in some cases have entirely abandoned the business. It has been found that the spirochete virus when imbibed will remain virulent within the tick during a period of six months fasting. Dodd (1910), who has recently studied the disease in Australia, reports that in one instance _ a fowl which was bitten by ticks that had fasted for 7 months and6 — days died with symptoms of chronic spirochetosis.
Lounsbury, who has permitted specimens of Argas miniatus and Ornithodoros savignyt to feed upon his arm, concludes that while they may be productive of considerable irritation and their penetra- tion serve as the entering point for some of the abscess-forming bac- teria, as may be said of all the ticks, yet otherwise their direct effect . is harmless. Nuttall and Strickland (1908) have found that the salivary glands and intestines of the fowl tick contain anticoagulin,
but no hemolysin. NATURAL CONTROL.
The habits of this tick are such as to protect it from natural ene- mies, although it is undoubtedly fed upon by rats and mice and devoured by fowls. To determine the effect of water upon it, 25 larvee which had hatched on September 1 were submerged on Sep- tember 9 and kept so for 174 hours, during all of which time they remained inactive. When removed from the water all proved to be alive and were again submerged and left until a total period of 654 hours had elapsed. One survived and lived for about two weeks following removal from the water. Thirteen larve which had hatched several days previous were submerged on September 12 for a period of 50 hours and none survived.
—
THE SPINOSE EAR TIOK. 61
ARTIFICIAL CONTROL.
It is not our intention to go into detail regarding remedial measures at this time, as a circular is being prepared from which the informa- tion may be obtained.
The larve, which may remain attached to the fowl as long as 8 days before dropping, are almost certain to be carried from one locality to another with the fowls. In order to prevent such dis- semination, fowls should be isolated in a tick-free cage or inclosure for 10 days before being transported to a tick-free house, as by the end of the period all will have dropped from the fowl. As it is the habit of ticks to crawl into cracks and crevices, it should be borne in mind that they may be conveyed from one point to another in shipping cages unless great care is taken. It is thought quite proba- ble that the larvee may be disseminated by pigeons and small birds.
The species is resistant to insecticides to a remarkable degree. When once this tick has become established in a poultry house, it is difficult to eradicate it entirely except through the use of fire. Much, however, can be accomplished by the frequent use of kerosene, crude petroleum, or creosote. Frequent and thorough cleaning of the poultry house and the application of one of these substances to the cracks and crevices will greatly assist in keeping the pest down.
Several plans for roosts which will prevent the ticks from gaining access to fowls at night have been suggested by Lounsbury (1903a) and others. In practice it has been found that roosts and nests sus- pended from the roof with baling wire will largely protect the fowls from tick attack. It is also important that the ticks be furnished with the least number of hiding places possible.
Genus ORNITHODOROS Koch.
Only one of the four species of the genus Ornithodoros which occur in the United States has been studied. Thisspecies,Ornithodoros megnini, appears to be the only one of the four that occurs in sufficient numbers to be of particular economic importance. Nuttall and Warburton in their monograph of the Argasidz have recognized 11 well established and 3 doubtful species as belonging to the genus. One of these, O. moubata, is of special importance, as it transmits human tick fever in Africa.
THE SPINOSE EAR TICK. Ornithodoros megnini (Dugés).
The common name of Ornithodoros megnini is taken from its habit of infesting the ears and from the characteristic spines on the body of the nymph.
' As previously stated studies of two other species (0. turicata and O. talaje) are now under way.
62 LIFE HISTORY OF NORTH AMERICAN TICKS.
DESCRIPTIVE.
Adult (PI. IV, figs. 6-9).—Female 5 by 3.5 by 2.5 mm. to 10 by 6 by 3.5 mm. Male usually somewhat smaller than the female. The adults are grayish to dark brown in color.
Nymph (P1. IV, figs. 2-5).—Unengorged, 2.25 by 1.5 mm. to 3 by 2mm.; engorged, 7 by 4 by2mm.to8 by5 by3 mm. The body of nymphs as they emerge from the larval skin have a blood-red color extending to the first two segments of the legs; otherwise they are a pearly white. Soon, however, they turn to a reddish brown.
Larva (Pl. IV, fig. 1)—Unengorged, about 0.55 by 0.30 mm.; engorged, 3 by 2mm.to 4 by 2.5mm. The seed ticks are dark gray in color, turning to a pink, then to a whitish color as they engorge.
Egg.—Spherical, dark brown, shining, smooth. The average size of 10 specimens measured ‘was 0.480 by 0.456 mm.
HOST RELATIONSHIP.
It is the habit of this tick to attach in the ears of the host, deep down in the folds of the concha and frequently in the external meatus. This habit appears to be more or less of an adaptation for protection, since they can not be removed by the host, or picked off by birds, and are not exposed to the attack of parasites.
The species was described from specimens taken from the ears of Mexican horses. Though collected more frequently from cattle than from any other host, it appears to attach to any of the larger mam- mals with which it comes in contact. In collections made in Texas and neighboring States by agents of the Bureau of Entomology up to January, 1911, 53 lots were from cattle, 11 from horses, 10 from dogs, 8 from cats, 3 from asses, 2 from mules, 2 from man, and 1 each from sheep and hog. It has been taken by Mr. H. 8S. Barber in Cali- fornia from the black-tailed deer.
GEOGRAPHICAL DISTRIBUTION. (Fig. 2.)
This tick was originally described by Dugés from Guanajuato, Mex., where it is said to be very abundant. We have found it to be a very important tick in certain parts of Texas, New Mexico, Arizona, California, and Mexico. Owing to the fact that it remains attached for long periods it may be widely disseminated on cattle, horses, and other animals shipped from an infested district. This fact doubtless accounts for some of the records from northern States. Up to the present time we have authentic records of its collection from the States of Kentucky, Iowa, Nebraska, Kansas, Oklahoma, Oregon, New Mexico, Idaho, Nevada, Arizona, California, Colorado, Texas, Louisiana, and Utah. The species was found in abundance by
.
THE SPINOSE EAR TICK. 63
Bishopp at Monclova, Durango, Torreon, Aguas Calientes, and Mon- terey, Mex. It is undoubtedly present throughout the greater part of Mexico and may be found to be distributed through Central and parts of South America when systematic collection is undertaken, as
Fig. 2.—The spinose ear tick, Ornithodoros megnini: Distribution. The large dots show localities where the species has been collected in our investigation. The small dots show the probable range of the Species. (Original.)
the Marx collection contains three lots with 15 well developed and 4 partially developed nymphs, which were taken from cattle in the Santa Lucia Mountains of Brazil. The accompanying map (fig. 2) shows approximately the normal range of the species in North
America.
64 LIFE HISTORY OF NORTH AMERICAN TICKS.
Although not recorded from Cuba, the species has probably been introduced there with cattle from the mainland, as large shipments of cattle from the infested districts are frequently made.
!
LIFE HISTORY.
Observations on the life history and habits of this species have been reported by Townsend (1893), by Hunter and Hooker (1907), and by Hooker (1908):
The egg.—With this species oviposition does not commence until mating has taken place. Large numbers of females have been iso- lated as nymphs in pill boxes and kept under observation for long
periods after molting but in no case were eggs deposited in the absence .
of males. Where females after molting were at once placed in pill boxes with males, oviposition commenced in a comparatively short time. Of 13 females thus isolated, 3 commenced oviposition on the eighth day after molting; all had commenced on or before the twelfth day, with one exception, in which case eggs were first laid on the fifteenth day. The largest number of eggs deposited by any one of these 13 ticks was 1,546, the minimum number was 358, and the average 814. The eggs last deposited by any of the 13 ticks were laid 191 days after the ticks molted.
Oviposition in this species is remarkable on account of its inter- mittent nature. One tick ceased deposition for a period of 83 days, then deposited a considerable number of eggs. This phenomenon is evidently not dependent upon climatic conditions.
The minimum incubation period observed in the laboratory was 10 days; 412° F. of effective temperature appear to be required for embryonic development.
TaBLeE XI.—Incubation period and larval longevity of Ornithodoros megnint.
ng in Mini- Temperature during incubation . mum
Eggs deposited. ee incuba- All larvee dead. ; ie Average | ‘Total
tion Maxi- Mini- daily eileg
period. mum. mum. mean. hinges
1908. 1908. Days. tl a a De oR: Mar. 150 No.0 3325 sae Apr. 4 Dhl cis eee emeaee 88.0 46.0 68. 03 526. 17 De Ree eee Apr. 16 OT te eh dn ste Stace ates 85.0 49.0 68. 72 540. 00 Mayowd2esesactes eeeeeae May 26 DSM oe ante 87.0 65. 0 76. 07 496. 00 11S eer ese eS sdo2 | oe ce os ee 87.0 65.0 76. 07 463.00 Pye ee May 27 DSRS? Stace. SELES ee 87.0 67.0 76. 98 441.75 Aes eee SU eee May 28 1D) eee es eA eae 87.0 68.0 77.33 412.00 DOE ea os We ee eae June 6 12 | Before July 9.... 88. 5 70.0 80. 64 444. 50 Ot ES aU are ter ME June 8 Lita ears donee ae 90.0 70.0 81.30 421. 25 DUNC. 4p set ne eee ees June 15 NRHP ARG eee Oe eee a 91.5 69.0 80. 19 446, 25 Site eee cS Re June 20 13 | Before July 9.... 91.5 69.0 80. 29 484.75 18) Fee ae Reet June 29 AM b ibe thie aa eee 90.0 73.0 81. 63 461. 50 Fe leer pees ety 3 July 10 125 ||| Fibers a 93.0 70.5 81.00 456. 00 Sealy BGs aaths Om | eR Aug. 4 10-702. bee ae 95.0 78.0 85.75 427. 50 Si se et ie yaelies Aug. 9 IO} aces See eee 99.0 73.0 86. 25 432. 50
THE SPINOSE EAR TICK, ORNITHODOROS MEGNINI.
Fig. 1—Unengorged larva. Fig. 2.—Slightly engorged nymph, dorsal view. Fig. 3.—Slightly engorged nymph, ventral view. Fig. 4.—Engorged nymph, dorsal view. Fig. 5.—Engorged nymph, ventral view. Fig. 6.—Engorged female, dorsal view. Fig. 7.—Male, dorsal view. Fig. 8.— (Orns pom which all eggs have been deposited, ventral view. Fig. 9.—Male, ventral view. Original.)
THE SPINOSE EAR TICK. 65
The larva (Tables XI, XII, XIII).—The seed ticks of this species soon succumb if exposed to moisture such as is required by the ixodid ticks when kept in tubes on sand. When kept in dry pill boxes after hatching some have died in a few days while others have lived nearly a month. On April 22, 1910, about 2,000 eggs deposited between April 8 and April 22 were placed in a tube out of doors. On May 19 most of the eggs had hatched. OnJuly 27 only 5 or 6 larve remained alive, and the last tick died August 3. Thus it appears that a period of 103 days may elapse from the deposition of the eggs to the death of the last larva. The larve usually remain in a dense bunch when not disturbed, but if aroused they become very active. Upon gaining access to the ear they attach to the sides of the concha.
As is shown in Table XII larve may molt as soon as the seventh day. In the five infestations recorded all had molted by the twelfth day after application to the ear. The appearance of the engorged larva has led several authors to speak of it as a pupa-like stage. It is not a resting stage, as the engorged larve move about when detached from, the host. However, there may be a brief period of quiescence immediately prior to molting as occurs in the case of most ticks.
The nymph (Tables XII, XIII).—The nymphs engorge very slowly
and require a comparatively long time for development. In feeding
they usually produce scabs, which peal off in layers beneath and about the tick, thus requiring occasional reattachment. There appears to be a great variation in the period that the nymphs remain upon the host. In our observations the first nymph to leave was found in the bag attached to the ear on the thirty-first day after
_ attachment as a seed tick or about three weeks after the larval molt.
Others have remained attached to the host for nearly 7 months (209 days) and would undoubtedly have remained longer had it not been that the host was unwittingly sprayed with naphtholeum by an assistant. Our observations indicate that nymphs when well en- gorged may at times be dislodged by violent exercise on the part of the host.
In order to determine whether the cotton bags tied to the ears influenced the ticks in leaving the host, the bags were removed at intervals, when the exact number of ticks attached in the ears could be determined. Apparently they were not thus influenced in any way. It seems quite probable that normally the nymphs leave the host at night while the latter is at a resting place, in the corral or stable. The fact that they crawl up several feet from the ground and secrete themselves in cracks and crevices of the boards and timbers near the mangers, in the bark of trees, etc., was first observed by Mitchell, as reported by Hunter and Hooker (1907). Hooker has noticed
21448°—Bull. 106—12——5
66 LIFE HISTORY OF NORTH AMERICAN TICKS.
this same habit in observations made at an infested dairy in the vicinity of Corpus Christi, Tex. The cracks and crevices in front of the mangers were examined and numerous adults (both alive and dead), eggs, and larve were found. The greatest number were secreted several feet above the mangers. By crawling up in this way they find the dry quarters that appear to be required for development. Such a habit is of advantage to the larve in finding their way to the ears of the host, as cattle using infested stalls or rubbing against infested trees and fences undoubtedly pick up large numbers.
Our records show that nymphs may molt as soon as the sixth day after dropping. The spines characteristic of the nymphal stage are shed with the molted skin and are not found upon adults.
The adult (Tables XII, XII1).—In the adult stage this tick never engorges blood, a habit, so far as known, unlike that of any other species of tick. During the long periods of feeding as a nymph, development appears to take place sufficiently so that oviposition commences directly following fertilization, which may be as soon as 8 days after molting, or possibly sooner. The females may live for long periods if they do not find mates; thus a female collected July 22, 1905, and kept isolated in a small pill box (molting 6 days later) lived until January 22, 1907, a period of approximately 18 months. During this period no eggs were deposited. The longevity of 13 females varied from 66 to 260 days with an average longevity of 138.5 days. Males were placed with these as soon as the females became adult (molted). The longevity of these males varied from 77 to 166 days with an average of 100 days. These males and females were the largest individuals selected from a considerable number of collected nymphs. The greatest adult longevity observed in our investigation exceeded 638 days.
As in other argasid ticks, the sexes may be readily distinguished by the shape of the genital opening; in the female it appears as a transverse slit, while in the male it takes the form of a crescent.
Mating.—The species has frequently been observed in copulation in pill boxes. We have never observed the proboscis of the male inserted in the vulva as occurs in Argas mimatus, although this prob- ably occurs. Christophers, who has studied ticks in India, states (1906, p. 9) that with Ornithodoros savignyi when placed in glass or porcelain vessels, a rapid tapping sound is sometimes heard which appears to be due to a vibration of the hinder portion of the body. We have frequently heard a tattoo-like sound made by adults of O. megnini kept in pill boxes and have considered it a sexual call. Upon removing the cover from the boxes the sounds have stopped and we have never observed a tick during the process. It appears that this habit is characteristic of the genus.
THE SPINOSE EAR TICK. 67
Taste XII.—The parasitic period of development of Ornithodoros megnini on a bovine.
1907. 1907. 1907. 1907. 1907. 1907. 1907.
INFESTATION No. 1.
Aug. 31,2p.m. Larve placed in ears.
Sept. 8, 9 a.m. (8th day). Several molted.
Sept. 9,9a.m. (9th day). All molted.
Oct. 4 (34th day). One nymph dropped, molted to a male 11 days later (Oct. 15).
Oct. 15 (45th day). One nymph dropped, molted to a male 13 days later (Oct. 28).
Nov. 5 (65th day). One nymph dropped.
Nov. 8 (62th day). One nymph dropped (8 by 5 by 3mm.), molted to a male 31 days later (Dec. 9).
1907. Nov. 18(78thday). Onenymph dropped (7 by 4 by 2.5mm.), molted to a male 13 days later (Dec. 1).
1908.
Mar. 13 (195th day). One nymph dropped.
1908. Mar. 27 (209th day). The remaining nymphs (3) dropped. These were probably atfiected by spray-
in
1907 1907 1907 1907 1907 1907 1907 1907 1907 1907 1908
g of the host Mar. 26. INFESTATION No. 2.
. Oct. 13, 11a.m. Larve placed in ear.
. Oct. 21, 9a. m. (8th day). One molted.
. Oct. 23 (10th day). All but two or three molted.
. Oct. 25 (12th day). All molted.
. Nov. 4 (22d day). One nymph was removed, molted (Nov. 28) 24 days later. . Dec. 3 (51st day). One nymph dropped.
. Dec. 4 (52d day). Two nymphs dropped.
. Dec. 5 (53d day).. Two nymphs dropped.
. Dec. 23 (70th day). One nymph dropped.
. Dec. 24 (71st day). One nymph dropped.
. Jan. 14 (93d day). The last nymph dropped (dead).
INFESTATION NO. 3.
. Apr.7,9a.m. Larvee placed in ear. . Apr. 14,4 p.m. (7th day). Two molted.
1908. Apr. 15 (8th day). All molted.
1908. Apr. 24. Three removed.
1908. May 8 (31st day). One nymph dropped (7 by 4 by 2 mm.).
1908. May 13 (36th day). One nymph dropped (7.5 by 5 by 3 mm.).
1908. May 17 (40th day). One nymph dropped (7 by 4.5 by 3 mm.). 1908. June 17 (7ist day). Four nymphs dropped.
1908. June 22-29 (76th-83d day). Two nymphs dropped.
1908. Aug. 7 (121st day). Two nymphs dropped (7 by 4.5 by 2.5 mm; & by 5 by 3 mm.).
1908. Aug. 11 (124th day). One nymph removed (7 by 4.5 by 2.5 mm.).
. Sept. 8 (154th day). One nymph dropped (7 by 4.5 by 3 mm.). . Sept. 24 (170th day). One nymph dropped. . Oct. 2 (178th day). One nymph dropped during process of spraying host.
INFESTATION No. 4.
. July 2. Larvee placed in ear. . July 12 (10th day). Several molted.
. July 14 (12th day). All molted.
. Aug. 26 (24th day). Cotton-seed oil poured into ear, but none dropped.
. Aug. 31 (29th day). One dead (in bag), 5 attached.
. Sept. 10 (39th day). Chloronaphtholeum (1 to 75) poured into ear but none dropped . Sept. 24 (53d day). One nymph dropped. ,
. Oct. 10 (67th day). One nymph dropped.
. Oct. 12 (69th day). Three nymphs still present.
INFESTATION No. 5.
. June 10. Larvee placed in ears.
. July 18 (8th day). Two molted.
. July 19 (9th day). Two molted.
. Aug. 6 (57th day). First nymph dropped.
. Oct. 1 (113th day). Last two nymphs dropped.
68 LIFE HISTORY OF NORTH AMERICAN TICKS.
TaBLeE XIII.—Suimmary of parasitic periods of Ornithodoros megnini.
Larve. Nymphs. First molted. Last molted. First dropped. | Last dropped. Total sr aa ee OE || BYE ion. : : Para- b : sitic Period Period) ~.4: Period Period i BANDE follow- follow-|, Sitic, follow- followed Date. |ingat-| Date. | ing at-|P ‘| Date. [ingat-| Date. | ing tach- tach- tach- molt- ment. ment. ment. ing. 1907. 1907. Days. 1907. Days. | Days.| 1907. Days. 1908. Days. | Days. Wy neees Aug. 31 | Sept. 8 | 8 | Sept. 9 9}; 89 | Oct. 4 34 | Mar. 27 201 209 Disisicrescte Octi a3) (Oct 28 | 8 | Oct. 25 12 | 8-12) Dee. 3 51 | Jan. 14 85 93 1908. 1908. 1908. 1908. Se sista Apr. 7] Apr. 14 (G.| eAtpre 5 8| 7-8 | May 8 Sib] O@ig 2 171 178 AY erates: <2 July 2] July 12 10 | July 14 12 | 10-12 | Sept. 24 53 | Oct. 121 59 69 1909. 1909. 1909. | 1909. 1909. Decca June 10 | July 18 | 8 | July 19 | 9| 89 | Aug. 6 oH | Och 105 113
| 13 attached.
LIFE CYCLE.
The larve may live under favorable conditions for 80 days. Upon gaining access to the ear they attach on the inside in the fold of the concha and even in the meatus, engorge, and molt in from 7 to 12 days. The nymphs engorge more slowly and digest blood as they develop. They may leave the host as soon as 31 days after molting or may remain for 201 days and probably longer. Upon leaving the host they usually crawl up several feet from the ground and secrete themselves in dry cracks and crevices. Here they molt, are fer- tilized, and deposit eggs. The incubation period in summer has been as short as 10 days. An effective temperature of at least 412° F. appears to be required for embryonic development. Unlike other ticks, this species never engorges blood in the adult stage.
The larve and more especially the nymphs are to be found on the host at all seasons of the year, although their seasonal abundance varies somewhat with local climatic conditions.
ECONOMIC IMPORTANCE.
This tick is undoubtedly of much more importance economically than is generally supposed. It is the source of great irritation to the host as evidenced by frequent and repeated shaking of the head. Townsend (1893) states that horses when badly infested have been known to roll as well. It is particularly injurious to calves which, unless treated and the ticks removed from their ears, frequently die as a result of the irritation. In some cases they run about shaking and rubbing the ears until exhausted. The milk yield of dairy cattle is undoubtedly lessened and in beef cattle the gain in weight correspondingly affected. On the range in the worst infested dis- tricts the loss of many head of cattle is chargeable to this tick. The deaths occur mainly during the winter and early spring, particularly
|
DEVELOPMENT OF THE IXODID®. 69
when feed is short and the cattle are poor. The ranchmen state that a heavily infested animal can often be told by the rough appearance of the hair.
There are numerous instances of this tick infesting the ears of man. Simpson (1901) reports a case in which two nymphs were taken, one from each ear of a gentleman in England who had camped in Arizona two months previous. The minute larve readily gain access to the external meatus of the humar ear, where they develop to nymphs before causing much irritation. Intense pain may be caused by its presence, but usually there are no serious consequences.
NATURAL CONTROL.
We have observed that occasionally nymphs, which enter the meatus, are killed by being coated by the wax secreted in the ears of cattle. No natural enemies have been observed. Considerable moisture appears to be injurious to the nymphs and adults.
ARTIFICIAL CONTROL.
Dairy cattle and calves in infested districts should be frequently examined, the ticks removed, and some mild oil introduced into the ear. Townsend (1893), reporting upon this tick as observed in New Mexico, states that ‘a mixture of 20 parts of sweet oil to one of laudanum is sometimes poured into the ear as a remedy, but is of doubtful efficiency.’’ Train oil, sometimes called British oil, he _ says, is highly recommended and he believes that it, as well as fish oil, will prove effective, but warns against the use of kerosene oil, which in the pure state has been known to cause temporary deafness. Townsend states that Dr. W. B. Lyon, of Las Cruces, N. Mex., rec- ommended a little chloroform or carbolic acid in sweet oil or the dust- ing of calomel into the ears of affected horses.
In order to determine the value of cottonseed oil as a remedy, on August 26, 1908, some of it was poured into the ear of a bullock upon nymphs which had developed from larve applied on June 2. The results were negative. On September 10 chloronaphtholeum (1 to 75) was poured into the ears of the same animal without causing any of the ticks to drop.
DEVELOPMENT OF THE IXODIDA.
The second of the two families, the Ixodide or typical ticks, is represented in this country by 8 genera, including 36 described species and 3 varieties.
As based upon their molting habits, the ixodids may be divided into three groups: (1) The one-host ticks, or those that pass both -molts upon the host; (2) the two-host ticks, or those which pass the first molt on the host but drop for the second, and (3) the three-host ticks, or those which drop for both molts.
70 LIFE HISTORY OF NORTH AMERICAN TICKS.
The life cycles of 15 species and 2 varieties, representing the genera Margaropus, Rhipicephalus, Dermacentor, Hemaphysalis, Ixodes, and Amblyomma, have been followed and are here considered. All molt twice and all but three drop from the host for both molts. Dermacentor mitens, Margaropus annulatus, and M. annulatus aus- tralis pass both upon the host. One other species, Dermacentor albvpictus, has also been found by us to pass both molts upon the host. Molting closely follows engorgement in species which do not leave the host, while with those which drop, a quiescent period of 6 days or more follows. Some species burrow into the soil to the depth of an inch or more to pass the quiescent period and are thus afforded protection and drying out is largely prevented.
As with the Argaside the oviposition, incubation, and molting periods vary with the temperature, while the periods of engorge- ment upon warm-blooded hosts are but slightly influenced. The female usually dies within a few days after oviposition is completed. The color of engorged ticks varies considerably, particularly in the immature stages; the color may be nearly white, pink, slate-gray, or black, dependent upon the comparative amounts of blood, lymph, and inflammatory exudate imbibed.
Table XIV shows the maximum and minimum periods of engorge- ment, molting, and preoviposition in the species studied by us. Owing to the fact that the figures for some of the species are based upon a small number of observations made at one time of the year, they are hardly comparable with others which are chosen from a larger number of records made under various temperature conditions.
TaBLe XIV.— Maximum and minimum periods of engorgement, molting, preoviposition, and incubation of the ixodid ticks treated herein.
Larve. Nymphs. Females. A Bebe es sid Incuba- Species. jane | Molting | BNE Ore, Molting nateeree: EE ae soda : | period. a period. : poster eggs. period. | P | period. period. | period. Days. | Days. Days. Days. Days. Days. Days. Amblyomma americanum...... 3-9 8-26 | 3-8 13-46 9-24 5-13 23-117 Amblyommacajennense........ 3-27 10-73 | 3-13 12-105 7-12 9-20 37-154 Amblyomma dissimile.......... 4-16 7-16 5-14 12-32 28 6 27-40 Amblyomma maculatum....... 3-7 7-121 5-11 17-71 14-18 3-9 21-10 Amblyomma tuberculatum.....|.......... 86-165 8-11 29-207 20-25 8-10 91-112 Dermacentor nitens ........._.- | (4) 8-16 @) 17-29 2 9-23 3-15 24-394 Dermacentor occidentalis ......- 2-7 6-12 o~ 13-22 7-10 4-17 21-38 Dermacentor parumapertus IMATPINAtUS 3-22-45 cee 4-14 8-39 125 21-123 9-26 5-6 20-24 Dermacentor variabilis.......-.. 4-7 7-11 18 6-25 8-16 5-14 24-43 Dermacentor venustus........-- | 2-8 6-19 3-9 1i-170 8-17 5-17 16-36 Heemaphysalis chordeilis.._._.. | 5-12 14-92 5-8 26-186 TOM ie yr sR eats »2s| 4202 Heemaphysalis leporis-palustris | 4-10 18-134 4-8 13-124 17-35 3-15 22-40 Exodestaincien 2 het Se sere rss 4-16} 27-163 5-66 29-94). | bss Sos 19-65 26-53 Ixodesiscapmlanisee sass) eae | 5-9 23-31 3-8 25-26 7+-30+ 15-16 72 Margaropus annulatus.........- | (1) 5-16 () | 6-20 25-19 1-66 19-202 Margaropus annulatus australis. (4) 6-9 | @) 8-13 27-13 1-7 24-34 a sanguineus. ....- | 3-6 6-29 | 49 | 12-29 6-50 3-83 19-142
1 This species molts on the host; hence the engorgement and molting periods can not be definitely sep-
arated, and are combined in the molting column.
2 These periods include the number of days from the molting of the first nymph to the dropping of the -
first engorged female, and from the molting of the last nymph to the dropping of the last female.
i é ‘
ee SS ee
DEVELOPMENT OF THE IXODIDA. 71
LONGEVITY.
The period of life of the free ticks while awaiting a host is of particular importance economically. In general the larve of the species which pass their molts upon the host appear to be shorter lived than those of other ixodid ticks. Dermacentor albipictus, which molts upon the host, is an exception, however, as the larve of this species exhibit great longevity. Moisture is one of the most important factors in determining the longevity of ticks. After larvee become weakened by fasting, a damp period has been observed to furnish conditions favorable to the development’of various fungi upon them and to result in the destruction of large numbers. However, a certain amount of moisture is essential. The absence of moisture, especially during hot weather, is even more destructive than an excessive amount. The free nymphs are usually longer lived than the larve; in a number of species they have been found to live as long as the adults. Accord- ing to Dixon (1910, p. 26) Lounsbury has found adults of Rhipicephalus evertsi to be alive, when kept in bottles, after a period of 18 months. Table XV summarizes our data on the longevity of the species observed. These records can not be considered as falling exactly into either of the two seasonal divisions used, as some were made during the spring and fall and others include part of summer and part of winter.
TaBLE XV.— Maximum longevity recorded for species of Izxodidz.
Larva. Nymph. Adult. Species. | Summer.| Winter. |Summer.|} Winter. |Summer., Winter. Days Days. Days. Days. Days Days. Amblyomma americanum,....-....-.---- 1150 2297 476 476 | 393-43 393-430 Amblyomma cajennense.........---.----- 2 386 2 386 408 408 466 466 Amblyomma dissimile...................- he eco ee Re Pei Fa See 129 103 Amblyomma maculatum...............-. 2107 £2 SOROS eae ae | 388-411 388-411 Amblyomma tuberculatum..............-|........-- 1 95-110 Sh ee eee hb Beemer es 2 BeerInaePTILO’ MICOS... <2. 22 eee nee Po EE ify BARES EE) SL Cer REE eee ae ae ee a Dermacentor occidentalis..............-.-- 2 105-124 281 69 76-108 243+ 2438+ Dermacentor parumapertus marginatus. -. 1 297 27 ip eS KOR ge SO) eee S Dermacentor variabilis........-.....-..-- 2 335 2335 | 200-216] 200-216 202 233 Dermacentor venustus...............-.-.- hi Silla aan 185 | 252-271 413+ 413+ Hecemaphysalis chordeilis................-. oe feo eee eal ee eee 74+ 305 305 Hemaphysalis leporis-palustris........... 2 258 2217 342 342 588 588 ONS See oe 6 RE ee ee 2209} 2215+ }.......... 68-171 1 Ba eey ss ee a ce Sh Be ees 75+ POSS Wee a ae Ae ee ee I RECS aE Marparopus annulatus.........-...-.....- 2125 i UC i 4 Seek eee! Wee Ae CO pe eed Dee at «3 Margaropus annulatus australis..........- Boe Bae yl Pe aS Oe Ss ee Cae = . Rhipicephalus sanguineus..............-- 280 | 2131-138 75 183 158 214
} Record based upon larve hatched from eggs deposited on 1 or 2days. Longevity computed from begin- ning of hatching to death of last larva.
2 Record based upon larve hatched from all eggs deposited by a female. Longevity computed from beginning of hatching to death of last larva.
PARASITIC PERIOD.
There are a number of factors that influence, more or less, the para- sitic periods of the ixodid ticks. Among these are the point of attach- ment to the host, fertilization, inability to detach, body temperature of the host, and, especially on cold-blooded hosts, the atmospheric tem-
12 LIFE HISTORY OF NORTH AMERICAN TICKS.
perature. Engorgement may take place somewhat sooner when the tick is attached at a place where the epidermis is thin and the hypo- stome reaches an abundant supply of capillaries than where the epider- mis is thicker and a poorer blood supply isfound. Usually ticks attach in favorable locations on the host’s body. However, we have found Amblyomma tuberculatum to attach to the edge of the carapace of the tortoise where the blood supply is exceedingly poor and prob- ably insufficient ever to produce engorgement. Few observations have been made on the variation in the time required for engorge- ment upon cold-blooded animals from that on warm-blooded hosts. The few records that we here present, however, are sufficient to show that much longer periods are required upon cold-blooded hosts even at summer temperatures. On such hosts the parasitic periods will undoubtedly be found to vary with the temperature to which they are exposed and, as the temperature falls, the difference between the parasitic period on warm-blooded and cold-blooded animals will probably be found to increase.
Upon warm-blooded hosts, fertilization appears to be an important factor influencing the engorgement of females. While they usually engorge quite rapidly after being fertilized, we have observed unfer- tilized females to dry up and die while awaiting a mate; others, apparently unfertilized, have been observed to engorge, though not to repletion, and usually much slower than fertile ones. However, in some cases at least, engorgement has been observed to proceed equally asrapidly in unfertilized as in fertilized ticks. Definite conclusionscan not be drawn inregard to this point until further observations are made. Some ticks do not engorge to repletion owing to the formation of scabs at the points of attachment, which are sloughed off along with the tick. Frequently, being unable to detach from the scab and unable to obtain blood, the tick dies attached to the host. Wehave frequently observed specimens which were very weak when applied to a host to die shortly after attachment. The species of ticks with short hypostomes often leave the host as soon as it is killed, but this is not the case with those having long hypostomes. Lounsbury (1899) has the following to say in regard to this habit:
Ticks of various kinds have been credited by different people with leaving an animal the moment death takes place. My observation does not confirm this state- ment. Mr. Roberts shot a badly infested cow while I was at Cottesbrook, and I was particular to watch the behavior of the ticks. None but a few fully-engorged blues [ Margaropus decoloratus] fell off at first. The pelt was removed and spread out on the grass. There were several dozen male tortoise shells [Amblyomma hebreum]and plenty of blues and reds [Rhipicephalus evertsi] and a few striped legs [Hyalomma xgyptium] present. Many of the males of all four kinds and a small proportion of the females detached themselves and wandered about the skin on the second and third days, but the majority of all kinds remained attached up to the fourth day, when because
of the unbearable stench I discontinued my observations. Later it was observed that vast numbers of the ticks had dried out without disengaging themselves.
a
ad ee ee ee
DEVELOPMENT OF THE IXODIDZ. 73
PREOVIPOSITION.
Following engorgement the female drops from the host, crawls to some protective covering, as into sand, cracks in the soil, beneath vegetation, litter, boards, or into cracks and crevices in buildings. In summer oviposition may commence as soon as the day following dropping, but usually the preoviposition period is of somewhat greater duration. In cold weather it may be delayed for as long as several
months. THE EGG.
The deposition of eggs continues in summer from one to two or more weeks, while during the colder months it may continue from one to several months. With the ixodid ticks oviposition occurs but once, during which time from one to many thousand eggs may be laid; with the completion of oviposition the female dies. The shortest incubation periods observed in the several species studied vary from i6 to 91 days. The longest incubation period recorded was 202 days. Temperature is the principal influencing factor, although humidity has some effect, particularly on the percentage of egos hatching.
The manner of oviposition by Ixodes was first described correctly by Gené (1845), and later by Bertkau (1881). Curtice (1892, p. 242) first described the process in Margaropus annulatus, Lewis (1892) in Amblyomma coronatum, and Wheler (1906) in Jzodes ricinus. <A de- tailed account of the process in M. annulatus has been given by Cush- man as reported by Hunter and Hooker (1907, p. 16). Lewis’s report of observations and that of Wheler are accompanied by illus- trations and Cushman has made a drawing which we here present (see p. 127, fig. 9) of the organ protruded by Amblyomma tuberculatum. During oviposition .the capitulum is retracted and a viscid vesicle to which Gené gave the name vesica biloba is protruded from between the capitulum and the scutum, from the lateral extremities of which two elevations are thrown out to be lengthened by evagination into two horns, lobes, or papille, as they have been described, which receive the eggs from the protruded oviduct. The glands of this vesicle secrete a viscid substance with which the lobes coat the eggs, thus causing them to adhere in a mass, and furnishing protection from drying. Gené found that eggs laid after destroying this sac, thus preventing the eggs from being covered, dried up and would not hatch, while others, newly laid by the same female and coated, hatched. Our observations appear © confirm those of Gené. In the case of the specimen of A. tuberculatum here figured, this sac was accidentally injured, resulting in the deposition of eggs which soon became dark and shrunken.
-
74 LIFE HISTORY OF NORTH AMERICAN TICKS,
THE LARVA.
Upon hatching, the larve of many species remain clustered to- gether for several days near the eggshells. Finally they crawl upon nearby herbage, such as grass, weeds, and even small trees, posts, or buildings, and there await the passing of a host. Some ticks, such as the species commonly found on dogs and rabbits, drop near the kennels or sleeping places of the hosts, and when the larve are ready to attach they may crawl about in search of the host.
Having once found a host the larve cling with great tenacity, crawling about over the body until a suitable place for attachment is found. The position of attachment upon the host varies with the species. Attachment may take place at once, or the tick may wander about for several days before attaching. This delay in attach- ment, the quantity and quality of the ingesta obtained by different specimens, and individual vitality account, in part at least, for the variation of from 2 to 14 days in the period between the applica- tion to hosts and the dropping of engorged larve from warm-blooded hosts and of from 10 to 18 days in the case of cold-blooded animals. After dropping, engorged larvee usually remain active for only a few days before becoming quiescent, during which time they crawl to some protective covering. In some species, however, a considerable period is passed before the engorged larvee become quiescent. From 10 days to several weeks may be required for the metamorphosis of the larva. This quiescent period varies primarily with the species, the temperature, and the humidity, the first two bemg the more
important. THE NYMPH. .
In general the longevity of the nymphs is somewhat greater than that of the larve. In awaiting the hosts, their habits are very similar to those of the larve. In those species which molt upon the host, the adults crawl from the nymphal exuvia and reattach rearby. The periods of engorgement are quite similar to those of the larve, but the quiescent periods are somewhat longer.
There is considerable variation in the size of the engorged nymphs. The smaller ones usually become males and the larger become females. In the species with color markings on the scutum, as in the species of Amblyomma, the markings can be seen through the skin that is about to be shed. The sex can thus be determimed from one to several days before the molt takes place. Following engorgement, if passed upon the host, molting takes place after a very short quies- _ cent period. With the species which drop for the nymphal molt, from 1 day to as much as 6 months of activity are passed prior to the quiescent period. During this period of activity the nymphs ~ attempt to find some protected place in which to transform. Par-
DEVELOPMENT OF THE IXODID&. 75
tially engorged nymphs usually have a much longer period of activity than fully engorged individuals. Low temperatures also lengthen this period. From 3 days to many months, varying somewhat with individuals, but particularly with the temperature, pass after the engorged nymphs drop before they transform to adults.
THE ADULT.
Upon molting, the adults may crawl upon herbage or other nearby objects and await a passing host. Some species, which commonly drop in places frequented by their hosts, may crawl about in search of them, as is the case with Rhipicephalus sanguineus. The lon- gevity periods are usually somewhat greater than those of the nymphs. In the case of those species which molt on the host, the female, after issuing from the exuvium, reattaches nearby, while the, male detaches and goes in search of a mate. Copu- Jation usually takes place upon the host, but with several species of Ixodes it occurs off the host as well. There are also several records of species of other genera where copulation occurred when the ticks were not on a host, but we are inclined to the opinion that, aside from ticks of the genus Ixodes, mating very rarely occurs off the host. The periods required by adults for engorgement are usually _ longer than those of the immature stages, as fertilization must, as a rule, first take place. We have found this period to vary consid- _ erably even in the same species. Fertilization appears to be one of the principal factors involved; the quantity and quality of the ingesta and the vitality of the individuals are also important factors. The rate of engorgement is greatly increased after the female has become about one-half engorged. Occasionally fully engorged females are unable to detach and remain attached for several days after becoming fully engorged. Our records show that females have engorged and dropped as soon as 5 days after attachment, while others have remained upon the host as long as 50 days.
It has been found that females in the course of oviposition may first produce fertile eggs and later eggs which are dark, shrunken, and apparently infertile. Specimens of many of the species when not over one-third engorged may be detached and if uninjured will reattach. There is a great difference in the number of eggs deposited by the various species, varying with the size of the tick and also with the size of the eggs. This variation in the maximum number of eggs deposited ranges from 2,240 per tick in Hemaphysalis leporis-palustris to as many as 11,265 by our native species, Amblyomma maculatum, and 20,000 by 2 African species (A. hebreum and A. variegatum). The _ males often remain upon the hosts for long periods after the females have dropped; thus the females usually do not have to wait long for a mate after findinga host. The habit of the male of remaining upon
76 LIFE HISTORY OF NORTH AMERICAN TICKS.
the host for a considerable time accounts for the fact that the males of the larger species, such as A. maculatum and A. tuberculatum, are more commonly collected than the females. It has been noted that with the species in which the male is small and inconspicuous the females have been more frequently collected.
Genus IXODES Latreille.
The genus Ixodes is represented by more species in the United States than any other genus. On account of this fact, the general distribution of the members of the group throughout the country, and the occurrence of the species on a large number of smal! mammals, no doubt a considerable number of undescribed forms will be found in the future.
The black-legged tick (/zodes scapularis) and the California Ixodes (Ixodes californicus) are the species of most importance in _ this country. These species are both closely related to the» European castor-bean tick (/xodes ricinus), and are thought by Bishopp to be only varieties of the European form. This view is also held by Nuttall and Warburton.
None of the members of this genus has been connected with disease transmission in this country, but in Germany Jzodes ricinus has been shown by Kossel and his associates (1903) to be capable of trans- mitting bovine piroplasmosis, and Stockman (1908) has shown it to play the same réle in England.
Ixodes ricinus, on account of its general distribution and impor- tance in Europe, has received the attention of a number of investi- gators. This species has been studied in England by Wheler (1899) and in Germany by Kossel and his coworkers (1903). Jzodes pilosus has been studied by Lounsbury (1900-1906) and by Mally (1904). The life histories of only two species of the genus, namely, Ixodes scapularis and Ixodes kingi, are presented here, although several other species are now being studied. All of the species observed drop from the host to pass both molts.
THE BLACK-LEGGED TICK. Tvodes scapularis Say. DESCRIPTIVE.!
Adult (Pl. V, figs. 2, 3, 5-8).—Males about 2.3 by 1.25 mm. Females, unengorged, from2.5 by 1.25 mm. to 3 by 1.5 mm.; en- gorged, about 10 by 7 by 5.5 mm. The females are usually dark brown, and the males almost black; scutum and legs in both sexes black, or nearly so. Partially engorged females that are nearly white, and others that are of a dark red color, are frequently found — upon the host.
1 The capitulum has been included in all the measurements of the length of this and other species recorded in this bulletin.
THE BLACK-LEGGED TICK, IXODES SCAPULARIS.
Fig. 1.—Unengorged larva. Fig. 2.—Male, dorsal view. Fig. 3.—Male, ventral view. Fig. 4—Unen- gorged nymph. Fig. 5.—Partly engorged female, dorsal view. Fig. 6.—Partly engorged female, ventral view. Fig. 7.—Fully engorged female, dorsal view. Fig. 8.—Fully engorged female, ventral view. (Original )
THE BLACK-LEGGED TICK. 17
Nymph (P1. V, fig. 4) —Unengorged, 1.5 by 0.75 mm.; engorged, from 2.3 by 1.5 by 1.25 mm. to 2.7 by 1.5 by 1.25 mm. Color, unengorged, dark smoky brown, shield and capitulum nearly black, legs lighter; engorged, dark bluish gray. Capitulum 0.317 mm. long (from tip of palpi to postero-lateral angles of basis capituli); scutum 0.586 mm. long by 0.491 mm. wide.
Larva (Pl. V, fig. 1)—Unengorged, from 0.616 by 0.371 mm. to 0.746 by 0.474 mm.; engorged, 1.28 by 0.76 mm. to 1.4 by 0.9 mm. Color, unengorged, smoky brown; scutum, capitulum, and legs somewhat darker than body; engorged, slate-gray to black. Capi- tulum 0.222 mm. long (from tip of palpi to base of emargination of shield); scutum 0.297 mm. long by 0.304 mm. wide.
Egg.—Size, about 0.445 by 0.386 mm. ; light brown, shining, smooth.
HOST RELATIONSHIP.
No type host was given by Say when he described this species. In certain sections of the South it occurs in considerable numbers on the dog and on cattle. The species has also been recorded from the deer, sheep, horse, and, in the immature stages, from birds, including the quail, blue jay, and thrush. One of the writers has found this tick to be common on the dog at Hawthorn, Fla. Mr. W. W. Yothers collected a number of adults on dogs at Orlando, Fla. Both
sexes were collected from an opossum at Hawthorn, Fla., and at
Tanglewood, Tex., Mr. C. T. Atkinson took a partially engorged
female on that host.
GEOGRAPHICAL DISTRIBUTION. (Fig. 3.) No type locality was given for this species by Say, who described it.
It appears to have been collected from Maryland south to Florida, and in the Central States from Indiana, Iowa, and Missouri, as well as in
_ Louisiana and Texas. A male specimen recorded from Pennsylvania
an
by Neumann may prove to be this species. Some 12 female speci- mens collected from Felis pardalis in Costa Rica and determined by Neumann as Jzodes affinis have been identified by Mr. Nathan Banks as I. scapularis. Mr. E. A. Schwarz took a male and female when he was beating hanging vines in heavy timber, a short distance west of Tampico, Mex.
LIFE HISTORY.
But little has previously been published on the biology of this species.
The egg—Two engorged females which were collected at Haw- thorn, Fla., on December 21, 1907, and sent to the laboratory, com- menced depositing, one on January 5, the other on January 6; 15 and
78 LIFE HISTORY OF NORTH AMERICAN TICKS.
16 days, respectively, after collection. The eggs deposited were not counted, but it was estimated that at least 3,000 had been deposited by one of the ticks. A well-engorged female collected on a cow at Dallas, Tex., November 24, 1908, began depositing on December 11, — thus having a preoviposition period of 17 days.
Fic. 3.—The black-legged tick, Ivodes scapularis: Distribution in the United States. The large dots show localities where the species has been collected in our investigation. The small dots indicate the probable range of the tick. (Original.)
In the laboratory at a mean temperature of 61° F., eggs deposited January 6 commenced hatching on March 17, an incubation period of ;
72 days. An accumulated effective temperature of 1,318° F. was required for their incubation.
Pha
THE BLACK-LEGGED TICK. 79
3 The larva (Tables XVI, XVID).—Larve which hatched in March have lived for 24 cain tlie in the laboratory and then attached to a
H bovine and engorged. Their longevity is undoubtedly considerably
F longer than this period.
_ Larvee were found to engorge and leave the host as soon as 3 days
_ after application, the longest period required being 9 days.
TaBLE XVI.—Engorgement of lurve of Ixodes scapularis.
Larve dropped engorged—days fol- Total
P | lowing application. num- Date larve applied. Host. | ber dro Py 1);2|3] 4 5|6/]7)]8]|9] ped | Pia ANE fo oso wee vweweaie ge wawe ses By BETS Bovine | 6-5 Or)-38-set ST 0.1 O17 .0.1. 0 35 OS EE Oe Eee ere reen® ae do 0] O| O} 1] Of} 7] 22] 3] 1 34 EE, SOM set hn Sy ap ok ow => ee gone mans ane + be 4 do Ler ah wie Of B | 0}. 8) @ 3 = RRR IRC HE: hy ee RO SD do 0| 0] 1| 0 0 0} 0} 0} o| 1
_ In May at a mean temperature of 77.19° F. engorged larve have
commenced to molt on the twenty-third day, the last to molt shed- ding its skin on the thirty-first day. Thus an accumulated effective _ temperature of 786° F. was required.
TaBLE XVII.— Molting of larvz of Ixodes scapularis.
|
Temperature from
Larve molted—days follow- | ditties tek! Weta
| | | | | | | , | ing dropping. | first tick molted. | Total Date engorged larve | F Wain meds ot ot LF OS reverse ETE peat 7 ial) molted. . -. Average | Ey 24| 25 '25|27|28| 2930) 2 axe | Mint | daily | | Poe aa "mean. em ee ed | ee Se ee eee ee ee ee ee eee ee ss Se Eee eee | au | oP. | oF. | oF. May TLL) a ae ae Bovine.. 18 OVE A1S 1S TROT LTO 14 | 88.50 63. 00 Zi. May 10, 1908...........|.-. o....| 2+4/213}/5/1/1}0]slolo 20 | 87.50 | 65.00| 77.19 US a ers ae Bi. 5 0;3/;21;0/0(10);0/0);0 5 | 88.50 | 65.00 77. 62 May 29, 1908...........|... a 4 |0|11]0| Othersdead.| 0| 0 1 | 91.50 | 69.00 72 many 30, 1908...........].-. oe: . 3 2;0/;0/;/0/0/0/0/0);1 3 | 91.50 } 69.00 80. 86 ai 1008...........|--. $1) 3 lololololololololi4 1 | 91.50 | 69.00| 80.90 aie. .......-:-|.. “Eo 2 /1/o0lololololololo 1 | 97.00 | 47.00| 86.64
The nymph (Tables XVIII, XIX) ity TERR of sil which molted in June lived 2 months 3 in the laboratory and then attached to host. Nymphs engorged and dropped as soon as the third day after application, the last to drop leaving the host on the eighth day.
TaBLE XVIII.—Engorgement of nymphs of Ixodes scapularis.
Nymphs dropped engorged—days | Total following application. num- Date nymphs applied. Host. | ber drop- | 1/2;3;4]5}]6)] 7] 8) ped. BETES « Salon's 4540 5a Gwaun eaian Bovine..| 0}; 0} 1] O} 3] L] 4] 2 11 NS a i rae | ae do....| 0} O}| O| OF} 1] L] OO} O 2 ES A adlin wicmnk <>'s ve cau ee ksdes cedars do....| 0/ 0} O| O}| 27 O} OF O 2
80 LIFE HISTORY OF NORTH AMERICAN TICKS. :
A nymph molted in June in 25 days, when the mean temperature — was 82° F. A total effective temperature of at least 955° F. was required. Thus an exceptionally high effective temperature appears | to be required for the nymphal molt. There is also a considerable variation in the periods in which the nymphal molt takes place. The length of the molting period of nymphs which become males is practically the same as that for nymphs which transform to females.
TaBLE XIX.—Molting of nymphs of Ixodes scapularis. [¢=Male. 9=Female.]
Nymphs molted—days following Number | Temperature from
2 dropping to date Date en: dropping. molted. first tick molted. gorged Num nymphs Host. |"jye 3 : © pb, dropped = . eH rs A g eel a 25|30|34/36/38|42| 43| 50| 52/56/53 |g|s] Xe | 88 B34 S —_ > sif&lea|s8@]s8 |4 ; a Ron ip June 23,1908 | Bovine.. | eee ee tO) a ees store eck Me eat Ke O} 24 D95.07) 70:5.) .eaeae June 25,1908 |...do....- 3 [fae ed1 22 SILO Aas ete OSE lct | aa 24 -3-] 95.0 | 70.55). S28ge June 26,1908 |...do....- 1) pA ea CE Tee (eee PSG one) esc Pee 1 1 94.0] 70.5] 82.20 June 27,1908 |...do..... Aas. Dest Clee ae ee sabes Lea Cesar il 4} 95.0 70.5 | 82.75 June 28,1908 }...do..... el ee | TR ee Seve ||) VO Para | ee eaceee| See s | ee e 0 if L 9520 70.5 | 83.45 July 15,1908 |...do..... 1 ee eel eel ee ecw ioe POUL CP st Shee ae 0 1 1 99.0 73.0 85. 28 July 16,1908 |...do..... Hil Pages| eee Pipette le | PO 1 RO) ee eee I ae 1 1 2 99.0 73.0 85. 76 Total). 4.2. rE [tpl iat [ig oS al Ma S| at 5| 8| 13
The adult-—The longevity of unfed males and females has not been determined owing to the limited supply of adults at hand. When removed from a host the adults do not live long unless kept quite moist; even the engorged females die unless they are kept under such conditions.
Males and females which would not attach when placed on a host — September 1 attached readily when given an opportunity 4 days © later. The following day they were found mated. On the morning — of the second day the males had detached, but in the afternoon they were again paired. One male remained with a female for 4 days, while others changed to a second mate during this time. Our obser-_ vations indicate that ordinarily mating is not continuous upon the host. It appears that mating may also take place off the host. We have observed an engorged, unattached female and an unattached male in coitu shortly after they were taken from the hair of a bunting dog. In the course of this act the mouthparts of the male are intro- duced into the genital pore of the female. |
A partially engorged female, collected in Florida, engorged and dropped on the seventh day after attachment to a bovine at the laboratory. A female applied to a bovine September 1 attached 4 days later and remained attached until September 25, when it was rubbed off by the host. At that time it was about one-third engorged, measuring 4 by 2.2 by 1.4 mm. A second female attached at the
|
THE BLACK-LEGGED TICK. 81
same time was sloughed off on October 1, being but slightly engorged at that time. The reason these two females did not engorge more rapidly is not known. It was not due to a lack of fertilization, as mating took place while the ticks were on the host. A slightly en- -gorged female that was applied to a bovine host on December 26, 1907, dropped 8 days later fully engorged, measuring 10 by 7 PY
5.5 mm. LIFE CYCLE.
Oviposition may commence in 15 days after dropping. Three thousand or more eggs are deposited by the engorged tick. In winter at a mean temperature of 61° F. incubation may take place in 72 days, a total effective temperature of 1,318° F. being required. Larve may engorge in 3 days and at a mean temperature of 77° F. com- mence to molt 23 days later, an accumulated effective temperature of 786° F. being required. Nymphs may engorge in 3 days after being applied to a host. In summer 25 or more days appear to be required for the nymphal molt. A total effective temperature of at least 1,017° IF. appears necessary for this transformation. A slightly engorged female collected on a dog reattached and engorged upon a new host in 7 days.
ECONOMIC IMPORTANCE,
The black-legged tick is not known to be of any great economic importance. In Germany and England a closely related species, _ Ixodes ricinus, transmits bovine piroplasmosis and it is possible that this species may do so. While this tick has been found by Prof. H. A. Morgan to be rather numerous on cattle in northern Louis- lana, it appears to be of minor importance as a cattle pest. In extensive collections made in Texas agents of this bureau have failed _ to find it in sufficient numbers to attract attention as a pest. In the vicinity of Hawthorn, Fla., however, it is the source of consid- erable annoyance to hunting dogs, and it has recently been found to be a pest of considerable importance to cattle and sheep in northern Tennessee.
NATURAL CONTROL. Observations relating to natural enemies of this species are lacking. ARTIFICIAL CONTROL.
Where hand picking is not sufficient to keep the species in control, mopping with one of the coal-tar products should be practiced. 21448°—Bull. 106—12——6
82 LIFE HISTORY OF NORTH AMERICAN TICKS.
THE ROTUND TICK, Ixodes kingit Bishopp.
The common name of this species is applied on account of the globular form of the engorged female.
DESCRIPTIVE.
Adult (PI. VI, figs. 4-9).—Males 2.85 by 1.51 mm. to 3.15 by 1.88 mm. Females, unengorged, 2.6 by 1.6 by 0.7 mm. to 2.7 by 1.7 by 0.7 mm.; engorged, 11.6 by 10.4 by 7 mm. to 13 by 12.8 by 8.5 mm.; unengorged males and females light yellowish brown; scutum somewhat darker; engorged females appear almost globular; shield and mouthparts inconspicuous; abdomen light blue-gray in color. The grooves on the dorsum and venter practically disappear on engorged specimens.
Nymph (Pl. VI, figs. 2, 3).—Unengorged, about 1.25 by 0.8 mm.; length of capitulum 0.37 mm. (from tip of palpi to base of emargina- tion of scutum); scutum 0.66 mm. long by 0.68 mm. wide; body ovoid, yellowish brown, somewhat translucent; engorged, about 2.3 by 1.3 by 0.8 mm.; slate color, legs and shield light colored as before engorging.
Larva (P1. VI, fig. 1).—Unengorged, 0.657 by 0.413 mm.; length of capitulum 0.19 mm. (from tip of palpi to base of emargination of scutum); scutum 0.277 mm. long by 0.335 mm. wide; body ovoid, very light yellow, translucent; engorged, 1.19 by 0.727 mm.; bluish gray in color. 7
Egg.—llipsoidal, light yellow, translucent. The maximum size of ten eggs was 0.541 by 0.420 mm.; the minimum size 0.528 by 0.392 mm. and the average size 0.534 by 0.401 mm.
HOST RELATIONSHIP.
The type host of this species is the badger. Our knowledge of the hosts of the immature, stages of this tick is limited owing to the diffi- culty met with in rearing immature stages of Ixodes to adults, and to the fact that the specific identity of the larve and nymphs of Ixodes can not be reliably determined. Immature stages of what are very probably this species have been collected upon the following hosts: Badger, larve and nymphs; pocket gopher (Thomomys clusius ocius), larve; marmot (Marmota flaviventer), larve and nymphs; skunk, nymphs; dog, nymphs; pine squirrel (Sciwrus hud- sonicus richardsonz), larve and nymphs; pika (Ochotona princeps), larve and nymphs; chipmunk (Eutamias), larve and nymphs; ground squirrel (Citellus columbianus), larve and nymphs. Many of the above lots were collected by Mr. W. V. King in western Montana. The sexes were taken together on badger in three
THE ROTUND TICK. 83
instances and on dog in two cases. Twenty lots have been col- lected in which females only were found. The hosts and number of lots on each is as follows: Dog, 8; pocket gopher, 2; prairie dog, 1; mink, 1; wolf, 1; spermophile, 1; marmot, 1; skunk, 1; kangaroo rat (Perodipus richardsoni), 1; unknown, 3. From the large number of ticks of both sexesfound on the badger it would appear that that ani- mal is one of the more important natural hosts of the species. We have been able to engorge the larve experimentally on the guinea pig, rabbit, and ox, and nymphs have been engorged on the guinea pig and ox. GEOGRAPHICAL DISTRIBUTION. (Fig. 4.)
The type locality of this species is Meeteetse, Wyo. The species appears to be widely distributed over the Western States from Texas to Montana. We have specimens which were collected in Texas, New Mexico, California, Utah, Wyoming, Idaho, and Montana. The tick appears to be most abundant in the northern part of its range. It is quite probable that this species occurs in Canada and possibly in Mexico, although no collections have been made in those regions.
LIFE HISTORY.
No studies have been made heretofore upon the biology of this tick.
The egg (Table XX).—Since specimens of this tick have not been engorged at the laboratory, only those sent in from various localities having been used in our studies, it is not possible to determine defi- nitely the relation between the length of the preoviposition period and temperature.
During June and July, 1909, a preoviposition period of 19 days was recorded. This is the shortest preoviposition period which we have ~ observed. The longest preoviposition period occurred during June, July, and August, 1909, and was 65 days. Four other specimens had preoviposition periods of 27, 28, 29, and 30 days, respectively. Deposition continued from 10 to 36 days. The shortness of the first period seemed to be due to the fact that the female was not fully engorged. The maximum number of eggs deposited by an individual was 4,706, and the average number 3,179. The females live but a short time after deposition is complete.
One female collected on June 23, 1909, began to deposit on the sixty-fifth day after collection. During the first 2 days of ovipo- sition 454 eggs were deposited. On subsequent days deposition con- tinued as follows: 104, 168, 169, 166, 107, 233, 59 (during 2 days), 43, 44,9, a total of 1,556 eggs being deposited during 13 days. A female collected June 29, 1909, began to deposit on the twenty-sixth day after collection. On that date and subsequent days deposition pro- ceeded as follows: 485, 226, 169, 231, 246, 156, 312 (during 2 days),
84 LIFE HISTORY OF NORTH AMERICAN TICKS.
104, 105, 109, 103, 113, 234, 97, 100, 115, 84, 94, 66, 69, 48, 10, a total of 3,276 eggs being deposited during the period of 133 days. A third individual, for which the date of collection was not recorded, deposited as follows: From June 9 to 11, 72 eggs. On subsequent
Fic. 4.—The rotund tick, Ixodes kingi; Distribution in the United States. The large dots show localities where the species has been collected in our investigation. The small dots show the probable distri- bution of the species. (Original.)
days, 319, 261, 372, 282, 306, 169, 181, 166, 130, 121, 105, 112, 148,
173, 142, 160, 152, 183, 102; 123, 121, 108, 118, 195, 80, 85, 115, 9
13 (during 2 days), a total of 4,706 eggs being deposited during the
period of 34 days. Many of the eggs deposited by the individual last
Bul. 106, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE VI.
THE ROTUND TICK, IXODES KINGI, AND THE BROWN DOG TICK, RHIPICEPHALUS SANGUINEUS.
Izodes kingi: Fig. 1—Unengorged larva. Fig. 2—Engorged nymph, dorsal view. Fig. 3.— Engorged nymph, ventral view. Fig. 4.—Male, dorsal view. Fig. 5.—Male, ventral view. Fig. 6.—Unengorged female, dorsal view. Fig. 7.—Unengorged female, ventral view. Fig. 8.— Partially engorged female, dorsal view. Fig. 9.—Partially engorged female, ventral view. Rhipicephalus sanguineus: Fig. 10.—Unengorged larva. Fig. 11.—Unengorged larva. Fig. 12.—Unengorged nymph. Fig. 13.—Unengorged female, dorsal view. Fig. 14.—Male, dorsal view. Fig. 15.—Partially ‘‘deposited-out’’ female, dorsal view. Fig. 16—Unen- gorged female, ventral view. Fig. 17.—Male, ventral view. (Original.)
) aes » * Vigd = ais bs ae : >, ¢ . ad cine * tae ~ me & t hie , “t ' G i* 4 its — oa 4 4 w a ie, »* a 4 fi £ a eae t no es lt =i y . vm q ‘ | 7) . \ ms ' 7 WY , ; Frog.
ca
THE ROTUND TICK. 85
recorded were shriveled and brownish and failed to hatch. Another fully engorged female, collected on a dog, March 29, 1910, began depos- iting on April 28, and deposited 130 eggs during the next 5 days. A few days later this female began to turn dark and soon died. The eggs deposited failed to hatch, thus suggesting that the tick may not have been fertilized.
The minimum incubation period observed was 26 days. This record was made in the laboratory during September, 1909, when the mean temperature was 85.67° F. A maximum incubation period of 53 days occurred during August, September, and October with a mean daily temperature of 84.58° F. The total effective temperature required for embryonic development appears to be at least 1,109° F.
TaBLE XX.—Preoviposition, incubation, and larval longevity of Ixodes kingi.
| t.
Temperature during incuba-
1% tion. E dj|D i- | Hatch oe ngor, eposi- atch- ecole tion ing incu- All larve dead. Bopckts pees, collected. | began. | began. | bation EeVIKy- see | Total period. Max.} Min. dail ef- mea, | Wttive 1909. 1909. 1909. Days. Days. 2F’. Fey fi, Be June 29..... July 25 | Sept. 1 39 | Feb. 25-Mar.30,1910.| 177-210..] 110 | 77 89.32 | 1,806.5 esate uly 29 ae <1 RS ie ae eer en eye cs me om i 89.25 | 1,618.8 10 70 eae Aug. 13°'| Oct. 4 53 | About May 1,1910..; About| 110} 66 84.58 | 2, 203.7 178. ee ..- Aug. 10 | Sept. 28 Se her ek Peewee SE aan Soe 110 | 56 84.74 | 2,387 Desi n-; Aug. 15 | Sept. 29 OG ss Sets. - ey. sek et oe 110 | 56 85.34 | 1,947.6 Dav... Aug. 18 | Sept. 24 38 | Apr. 27-July 19,1910 | 215-298..| 110 | 61 86.65 | 1,658.7 Dass: .. Sept. 1] Sept. 26 OG) | ease pete eee so Ret EE ee ee 101 | 61 85.67 | 1,109.4 1910. 1910. 1910. Mar, 29..... Apr. 27 | June 17 52 | Before Sept. 25, 1910.| 100...... 100 | 62.75 | 75.36 | 1,682.7 70) ay (ae ay 16] June 24 AO es asd 2b. S522. Ast eeetae . 100 | 60 80.61 | 1,504.4 MAY Cen cs June 1) July 14 pF ST 2) ot Pan 3s a ee 1 es 100 | 66 84.51 | 1,826.4 June 18..... July 5| Aug..5 O20) Webs 4h01le o. u03-t BSS! ecg? 104 | 73 88.09 | 1,442.9
The larva (Tables XX—XX1T).—The larve of this tick have been found to live at least 215 days. The lot upon which this record was based hatched September 24, 1909. Fifty were still alive April 27, 1910. Other lots hatched in midsummer were found to live nearly as long as the one cited. Larve may drop engorged as soon as the fourth day after application to a host, while some may remain on the host 16 days and even then not become fully engorged. Although no engorgements were obtained from two or three lots of larvee applied to bovines and guinea pigs, most of the lots tested attached readily and a large percentage of them engorged. Attachment was found to take place usually within an hour after the time of application to a host. Many specimens were found detached from the host when they were from one-fifth to two-thirds engorged. This premature drop- ping is probably due to the ease with which they are displaced by the host animal after they have become partially engorged.
* 86 LIFE HISTORY OF NORTH AMERICAN TICKS.
TABLE XX1.—Engorgement of larvx of Trodes kingi.
Larvee dropped engorged—days following
lication. Date larvee HOS Num- appicauen ONE State of applied. ats ber. = dropped. engorgement. 4 | ae FeCl aa | So) Oe sh 144-15 106 eS AN A 8a i a SE 2 ee Lop ded ch! Sept. 15,1909 | Guinea pig.) 120] 0] 11] 51/25) 8) 5 100 | One-half to fully. Oct. ,.1,1909 Rabbit. ouisali alle aclu nt eee Solcan Oct. 28,1909 | Bovine.....| 100} 4/ 7]15] 5| 6 | 37 | One-half to | full Nov. 4,1909 |..... don. 100 | 27 | St ote ie 66.0. oc) Nov. 16,1909 |..... gok 100 0} @) p15 ts eee ee Te a 32)... case ar Jan. 14,1910 | Guinea pig.} 110 Hh) OF) OG eG 205] SO eo ences |e | eer 8 | One-half to two- thirds. Sept. 28,1910 |..... doe 40170) OO) 0) 07) 0 ROLE) bye 13 | One-fifth to | | fully. motalel Geto cael cela fee eeleedien lee 259
1 The larvee which dropped on this date were included with those which dropped on the following day.
The larval molting period varies greatly, as was shown in experi- — ments in which 54 individuals were observed, and seems to be gov- erned mainly by temperature conditions. The shortest molting period observed was 27 days; the longest, 163 days. The mean temperature during these two periods was 74.43 °F. and 59.65° F., respectively. A total effective temperature of 821.1° F. appears to be required for this transformation. The large percentage of mortality during molting in some of the lots was probably due in part to the fact that a considerable number of individuals was not fully engorged when detached from the host. Durmg summer, when the molting period is shorter, the mortality would probably be smaller, as the effect of drying out would not be so great. Undoubtedly humidity is an important factor, at this stage of their development.
The nymph (Tables XXII-X X1I1).—Of 20 nymphs which molted to larve between January 29 and April 2, 1910, 16 were put on hosts during March and April. The last individual of the four remaining died between June 9 and July 19, 1910. Thus the longevity of these 4 individuals was between 68 and 171 days. Another lot of 8 nymphs, which molted from larve between March 22 and April 4, 1910, died — between June 9 and July 19, 1910, thus living for a period of 66 to 119 — days. The minimum nymphal engorgement period recorded was — 5 days. In one instance a nymph remained on the host 66 days, at — the end of which time it was accidentally detached when only two- thirds engorged. Attachment was usually found to take place soon after application, but occasionally nymphs remained in proximity to — a host for 36 hours before attaching. The readiness with which attachment takes place and the rate of engorgement appear to depend to some extent upon the vitality of the individuals when ~ applied. If nymphs are weak when applied to a host they are usually slow in attaching, and frequently many die on the host
a ee ae eee
Re ROE ny Pa ee nn ek nn
THE ROTUND TICK. 87
before becoming engorged to any extent. Guinea pigs and bovines were the only hosts upon which nymphs were placed for engorge- ment in our experiments.
TasLe XXII.—Engorgement of nymphs of Ixodes kingi.
Nymphs dropped—days fol-
Num- lowing application. Total
Date nymphs cat Num-|_ ber num- | State of engorge- applied. : ber. at- ber ment.
tached. 5 7 | 15 16 66 \dropped Oct. 25,1909 | Bovine....-... 1 iT eee | (eae | a et, ae ee 1 | 1 | Two-thirds. Nov. 11,1909 |..... OMe o% 5 VD OR ess be oe 1 ne See 3 | Fully. Mar. 29,1910 | Guinea pig... 8 ft ae Sees oe epee £5 ae 1 | Four-fifths. Apr. 14,1910.| Bovine....... 1 1 gO a Se |S a | ea a Ra oe 1 ully. Apr. 19,1910 |..... 1 eg eee 8 Abe ose if Pete's 4 tbr ee 2 Tse tote to " ully.
- Of a large number of nymphs applied to hosts only 3 were brought to the adult stage. The records on these were made during April, May, and June, 1910. The molting periods for these 3 individuals, all of which were females, were 29, 33, and 34 days, respectively. An average daily mean temperature of 73.29° F. was recorded during the minimum molting period and a total effective temperature of 878.4°F. was accumulated.
TaBLeE XXIII.—Molting of engorged nymphs of Ixodes kingi.
Pears aypensl a ee molted—days 7 emperature from dropping following drop- Number molted. to dato first tick molted. Date engorged : pimg. nymphs ap- | Host. fa plied. | agg x Fe- Maxi- | Mini- | “vorase | | 29 23 34 | Male. aie: Total. aol canis eon Oi. (nie 1 1S OLE yiame Waits (i Para Greta: ii ae °F. ae °F: Apr. 19,1910 | Bovine....| i so Er | re RS 1° 0 1 1 90.0 51.50 71. 87 Apr. 26,1910 eas i | ead ES Ree eae) eB ae 0 1 1 90.0 58. 50 73.29 May 4,1910]|...do...... ae 58 rio} eagetd ihe 1 1 100. 0 59. 00 76. 34 Total | 3 | <bitae AS | [F ene | eee | ae Tap | 3 3 | |
The adult—One individual of a lot of 3 females which molted between May 23 and June 6, 1910, lived about 104 days. One par- tially engorged female lived 102 days after being removed from a host on September 20, 1909. This tick appeared to be killed by the cold. Owing to the fact that very little material was reared to the adult stage and both sexes were not obtained at the same time, no records of engorgement were obtained. One female put on a guinea pig attached in a few hours and died on the host during the second day after application. This tick appeared to take some blood prior
to its death.
88 LIFE HISTORY OF NORTH AMERICAN TICKS,
No observations have been made on mating. Very few males have been collected in nature as compared with the number of females
taken. Making allowance for the fact that some collectors may have
overlooked the males, it appears that females are much more abundant on hosts than are males.
The engorged females are usually well covered with a yellowish waxy substance, apparently secreted on all parts of the less chitinized integument. This substance frequently accumulates in considerable masses around the capitulum and genitalia. The engorged females are almost globular, and the legs are delicate and scarcely touch the surface upon which the female lies. Movement of the engorged females is therefore practically impossible.
LIFE CYCLE.
Larve may live for at least 215 days. They may engorge in 4 days and molt as soon as the ninth day after droppmg. The longest molting period recorded was 163 days. A total effective tempera- ture of at least 822° F. appears necessary for this molt. Nymphs may live for at least 66 days in summer and probably longer in winter. They may engorge as soon as the fifth day after application and molt
as soon as the twenty-ninth day after dropping. A total effective ©
temperature of 878.4° F. is required for the transformation to adult. The length of the engorgement period of females has not been deter-
mined. The shortest preoviposition period was 19 days and the © longest 65 days. Deposition may continue for 34 days and as many ~ as 4,706 eggs be deposited. Eggs may hatch as soon as 29 days after —
deposition and appear to require a total effective temperature of |
1,109° F. for incubation. All stages seem to be most numerous on hosts in midsummer,
although we have specimens collected from March to November.
Further investigation will probably show them to be present on hosts in greater or less numbers throughout the year.
ECONOMIC IMPORTANCE.
This tick has never been recorded as a parasite of man or of domes- tic animals other than the dog, and since it seldom occurs in great
numbers on this host it appears to be of practically no economic —
importance. NATURAL CONTROL.
No natural enemies of this species have been recorded. Eggs in a
bunch of about 100 which were exposed to the sun on the ground for
about 3 hours all shriveled and failed to hatch. During this period — the highest atmospheric temperature was 110° F. and the highest —
soil surface temperature was 133° F.
THE RABBIT TICK, &Y
Genus HZEMAPHYSALIS Koch.
Two species of the genus Hemaphysalis occur in the United States both of which are quite widely distributed. One of the two (Hzma- physalis chordeilis) is of economic importance on account of its habit of attacking turkeys. The life history and habits of 3 exotic species have been studied, namely, H. leachi, the active agent in South Africa in the transmission of canine piroplaamosis, by Lounsbury (1902, 1904, 1905), H. prozima in Brazil by Rohr (1909), and H. punctata, which has been found by Stockman (1908) to transmit bovine piroplasmosis. This latter species has recently been reported by Hadwen (1910) to occur in Manitoba. It must have been intro- duced from abroad, probably on cattle from England, where it is a very common pest. All three of these foreign species, as well as the two species (H. leporis-palustris and H. chordeilis) which have been studied by us drop from the host for both molts. One of the authors (Hooker 1909a, pp. 252-253) was led to believe that this species molts on the hosts on account of molted skins of larve being found on the heads of quail associated with larve and nymphs belonging to the genus Hemaphysalis. We have since reared H. chordeilis and as we have had considerable numbers of both the larve and nymphs to drop from the hosts engorged and then molt, we must conclude that the skins found on the quail were shed by individuals of some other bird-infesting species.
THE RABBIT TICK. Hemaphysalis leporis-palustris Packard.
The rabbit tick (Hxemaphysalis leporis-palustris Packard) is so named from the fact that it is the most widely distributed and common tick which attacks the rabbit in the United States.
DESCRIPTIVE.
Adult (Pl. VII, figs. 4-6).—Males from 1.6 by 1 mm. to 2.25 by 1.25mm. Females, unengorged, from 2.25 by 1.25 mm. to 2.5 by 1.5 mm.; engorged, from 6 by 3.5 by 2.5 mm. to 11.3 by 7.5 by 5.3 mm.; males and females very dark brown or black in color with no light markings; engorged females slate color.
Nymph (Pl. VII, figs. 2, 3).—Unengorged, about 1. 33 by 0.8 mm., dark reddish brown; engorged, 2.5 by 1.75 mm., dark bluish gray to almost black; capitulum 0.218 mm. in length (from tip of palpi to postero-lateral angles of basis capituli); scutum 0.422 mm. long by 0.436 mnt. wide.
Larva (Pl. VII, fig. 1).—Unengorged, about 0.534 by 0.385 mm.; dark smoky brown; scutum lighter in center; engorged, about 1.33 by 0.88 mm; ovoid, very dark brown to black, often with a pink tinge
90 LIFE HISTORY OF NORTH AMERICAN TICKS.
for some time after dropping; capitulum 0.164 mm. long (from tip of palpi to base of emargination of scutum) ; scutum 0.246 mm. long by 0.305 mm. wide.
Egg.—The average size for 10 eggs which were measured was 0.493 _ by 0.396 mm. Ellipsoidal, dark brown to black in color, shining, — smooth.
HOST RELATIONSHIP.
The hares and rabbits are the principal hosts, especially of the adult stage. (Lepus) Sylvilagus palustris is the type host. We have . collected the tick on about 7 species of rabbits, and have also taken — the adults on robin, quail, meadowlark, and domestic cat. The im- mature stages have been taken in abundance on quail and meadow- lark and in fewer numbers on chaparral cock and Brewer’s black- — bird. Immature stages of what are probably this species were taken on the thrush, field lark, jackdaw, blue jay, magpie, and pine squirrel. A single nymph was taken on a groove-billed ani at Victoria, Tamaulipas, Mex., and a larva, probably of this species, was taken on a smal! sparrow at Monterey, Mex. On rabbits the species is nearly always found attached to the ears, either inside or out. On birds the ticks are nearly always found upon the head, largely upon or about the crest. However, occasionally they attach on the neck and about the eyes and ears.
GEOGRAPHICAL DISTRIBUTION. (Fig. 5.)
The type locality for this species is North Carolina. The species occurs in many States, from Massachusetts to California and Mexico. The States from which the species is recorded are Alabama, Arizona, Arkansas, California, Colorado, Florida, Idaho, Illinois, Kansas, Louisiana, Massachusetts, Minnesota, Montana, New Mexico, New York, North Carolina, Nevada, Oklahoma, Oregon, Tennessee, Texas, Virginia, Washington, and Wyoming. It has also been taken in
~Mexico. In western Texas, New Mexico, and Arizona the species is not commonly found, the rabbit Dermacentor being the tick ordina- rily met with on rabbits. We have taken it in large numbers from rabbits in Montana and neighboring States.
LIFE HISTORY.
Observations on the biology of this species have been reported by Hunter and Hooker (1907) and by Hooker (1908, 1909).
The egg (Tables XXIV, XXV).—In one instance oviposition began on the third day after dropping. The mean temperature during this period beginning June 15, 1909, was 89.5°F. The longest preovi- position period observed was 15 days. This record was made on a
THE RABBIT TICK. 91
well-engorged female collected March 7, 1910. The mean tempera- ture for the period was 68.62° F. The average preoviposition period of 25 ticks observed during the spring and summer months was 8 days. The engorged female is usually comparatively small, due
Fic. 5.—The rabbit tick, Hamaphysalis leporis-palustris: Distribution in the United States. The large dots show localities where the species has been collected in our investigation. The small dots show the probable distribution of the species. (Original.)
probably to the fact that it is confined to the smaller mammals and to bird hosts. Owing to its rather small size it deposits comparatively few eggs. Eight females were under observation. The largest num- ber of eggs deposited by a single female was 2,240; the smallest
99 LIFE HISTORY OF NORTH AMERICAN TICKS.
number was 59, and the average number was 1,517. This maximum record was made by a fully-engorged female collected on a rabbit May 7, 1909. This was the largest engorged female seen by us, measuring 11.3 by 7.5 by 5.3 mm. Deposition began on the seventh day after collection and continued for 20 days. The largest number of eggs deposited during one day was 303, which occurred on the first day of oviposition.
The preoviposition period of the eight females ranged between 4 and 9 days, with an average of 6.4 days. The period of oviposi- tion varied from 5 to 20 days. The female having the shortest Oviposition period probably died prematurely. Death of the females usually took place on the day following the completion of egg laying. In one case it occurred on the fifth day after deposition ceased.
Eggs kept out of doors were, in one instance, found to hatch in 22 days. The mean temperature during this period was 90° F. and the total effective temperature 1,034° F. In the laboratory the incu- bation period has been found to be as short as 23 days for eggs deposited in June. During this period the mean temperature was 82° F., an effective temperature of about 902° F. being required for
hatching. The longest incubation period observed in about 25 lots
of eggs deposited during the spring and summer was 40 days.
TaBLE XXIV.—Incubation and longevity of larve of Hxemaphysalis leporis-palustris.
| | Temperature eee incubation eriod. Mini- - Hatch- | mum Larval Eggs deposited. ing incu- All larvee dead. lon- eae began. | bation gevity.| woaxi- | Mini = Total period. sp _ ge effec- mum. | mum. | daily tive mean . Days. Days. eae oe °F. | "Kh May 20-23, 1906_......} June 20 32) Maras. lOO aca tee 258)" | it ode. Alo. aca h Rage ee May 24-29, 1906_._....| June 23 Sie |e Ae Most we SE 255 coe Soe Sales ata eee | Sept. 2-5, 1906__...... Sept. 26 25) May 1, 190725 8 eis a] Meee alee ees |e ee Sept; 4, 1907253. =: Sept. 27 24 | Apr. 13, 1908 (sev- 199+} 102.0 50:10) |) 78. 7 821.5 eral alive). Sept. 7-9, 1907._......| Sept. 30 24 | Mar. 17, 1908 (one 168+} 102.0 bOLO)| Wias 788. 5 alive). June 29, 1908......... July 21 93.\| Sept oietsogh ete. Gs 94.0] 70.5 | 82.25} 902.75 May;6,,190922. 2242-8 June 8 34 | Jan. 22, 1910 (one 228-++ 89.5 59.0 | 81.49 {1,308.75 alive), June 18, 19091_....... | July 9 22 | Sept. 18-28, 1908__...| 71-SO 102.0 81.0 | 90.0 {1,034.00 Apr i4: ASLO sf asks | May 23 40 | July 19 to Aug. 20, | 57-89 90.0 51.5 | 70.91 {1,116.50 1910. May 7, 1910__.........; June 9 34 |... -- GOs ar eS R072 | 100.0 59.0 77.29 |1, 285. 75 June —, 1910......... Fialive 14 eee 2 Hebsis lols oe eee ee 204 i Sree ee nee asailecoc: =. -
1 This lot was kept out of doors.
The larva (Tables XXIV, XXV).—The longevity of the larve has been found to be as great as 258 days under favorable conditions. The larve which survived for this period hatched on June 20 and thus passed through the summer months, which are the most unfavorable to long survival. Many lots of larve which hatched early in the summer of 1909 died in about two months. The excessive heat dur-
THE RABBIT TICK. 93
ing August of that year was at least partially responsible. Engorged larve have dropped from rabbits as soon as the fourth day following attachment, but on a bovine 6 days was the shortest period of engorge- ment. The greatest number drop from the fifth to the eighth day, 10 days being the longest time required for engorgement.
TABLE XX V.—Engorgement of larve of Hemaphysalis leporis-palustris.
| | Larve dropped engorged—days following application.
4 Total siege = | Host. | number | 1 2 | 3 fag Hegde ey th Bede | dropped. Re eb Rt Pileliet. os alive hip cet aed ‘de I Sept. 30, 1907.....| Rabbit... 0/ of] of] o| 25] 27| 33 ae en 98 eG 2, TOO... - 1-240. 25 <2 0 0 0 5 77 a 1 2 5 | 4 | 192 Nov. 15, 1907. .... Bovine 0 0 0 0 19 75 | 27 11 | 2 | 0 134 Mar. 11, 1908.....|... age eT by) OUT eT 13| 19 40" OV" 6 36 Mar:.19,1908. . ..:\ese ee 0 0 0 0 | 11 131 115 24 0 | 0 281
The molting of engorged larve was observed in 384 cases. Larvee which dropped in March at a mean temperature of 68.7° F. molted in 18 days, an effective temperature of 463° F’. having been required. The longest period passed before molting was for 2 larve which dropped November 22, 1907, and molted 134 days later. The mean temperature during this period was 61.98° F. Unfortunately our records do not include individuals which engorged during the summer months.
The nymph (Tables XX VI, XXVII).—The greatest nymphal lon- ' gevity observed was 342 days. This record was made on two nymphs which were collected on a rabbit on June 19, 1909, by Mr. W. V. King. One of a few nymphs which molted from larve April 19, 1908, lived for 307 days. A number of other lots of ticks, which were observed from the time they molted to nymphs, lived from 78 to 246 days. The longevity of a number of lots of collected individuals, which had become from slightly to one-half engorged, was from 34 to 334 days. The minimum engorgement period of nymphs which we have ob- served was 4 days, the last ticks dropping on the eighth day after application.
TaBLE XXVI.—Engorgement of nymphs of Hemaphysalis leporis-palustris.
a GIRS Sa SS EAE 8 te eee eS ae seme
plied. ; : dropped 1 2 3 4 5 6 7 8 9 10
Oct. 29, 1907......| Rabbit... 0 0 0 0 0 2 1 0 0 0 3
Feb. 25, 1908..... Bovine.... 0 0 0 0 0 1 0 1 0 0 2
Apr. 4, 1908...... Ph aelee Se oe 0 0 0 0 0 3 6 | 2 0 0 11
June 2, 1908......)... Uae 0 0 0 5 24 14 2 | 0 0 0 45
May 22, 1909......| Rabbit 0 0 0 1 0 0 0) 0 0 0 1
~
94 LIFE HISTORY OF NORTH AMERICAN TICKS.
Nymphs which dropped June 8, 1908, and were kept at a mean temperature of 80° F. commenced molting on the fourteenth day after dropping. A total effective temperature of 486° F. accumu- lated during this period. When the mean temperature was 58.34° F. molting began on the eighty-ninth day after dropping. The longest period from dropping to molting which we have observed was 124 days. The last three lots of ticks, the molting of which is recorded in the following table, were collected from wild hosts and were not
all fully engorged.
same.
This may have tended to lengthen slightly the molting period of some of the individuals.
The nymphal molting period of the two sexes is practically the Our observations indicate that a very large percentage of the engorged nymphs reach the adult stage even when dropping takes place in the winter.
TaBLE XXVII.— Molting of engorged nymphs of Hemaphysalis leporis-palustris.
Date Engorged ny.uphs molted—days following dropping. engorged : Nuin- nymphs Host. ber. | dropped. 13 | 14 | 15] 16 | 25) 26 27 | 29 30 | 48 49 | 53 | 58/84! 85 | 89 | 94 |96/ 97 |98 BA es REAM Coit fey) Bot) Tea ale SRE hs 2h A | ae eee Cine | Nov. 4,07 | Rabbit_... 1 OM OF O"} SON 4080 0/0 0 0 PSO OO SO SOF OF OF Oate INOW .D07 822500). 5 7-0 1 Ot e Ow) OMe OF POs) Os0 19] 01.0 1.0) 0) 20) 0 | <0) Oona Apr.10,08 | Bovine_- 3 ON}? Of Os ONO ONL Oa ROMO) Oy 40.1105) 10) 120 Oi On OR ROM ine AD ToUn OSs | CORe ae 6/105) Oo COR On Sao IgS1 9/19) 0 OF) O30 10 15205) OO) On One Apr.12,08 |...do...... 2| 0] 0/0] ojo {13 fo | o}o|o/ol/ol/o/]o] of of Ololola June 6,08 |...do.....- 5 0 fta{i Slee 0} O1O|0|0/0/0\0/0/0] o| 0} ovavom | . | | ‘ 28/482 larwidl Tune 7,08.|.-sdo. a -0 24 | 0 sooo} 0} 0/0/0/0 o}o/o}ojo} 0} 0} ojojolo June 8,08 |...do...... 14 {13198 49/14/0] 0/0)0]0/0);0/0/0]0] o| 0] ofojojo June 9,08 |...do...... 2/ 0] Oj1s] 1/0] 0/0/0)0/0]/0/0]0/0] 0] 0] of 0]o0}o Noy.10,08 | Quail..... FOO Or Oo 0]-0/0/0/0) 0/0919; 0) 0] 0} OJo/ojo Nov.25, 09 retell DH MOO VOl) ONT OR MONON TOON OMRON ORO On| a On in: O 507) 2aie2 Dec. 29,09 haparral | ld Spay BHO, Dale 0}0) O}0/o)0,ofojo/o oj raf ehhahe| ojo Total! ke ree Ee f Pike P/N Diao ah Teen ae ia ey emu! | | Lal ae | Engorged nymphs r y ‘ molted—days fol- Number molted. P Soa teers crepe Date lowing dropping. + eb ae engorged |Num- nymphs eb. ber. | | | ropped. Meee Mini- | 4verage 100 | 104/112) 113/124} @¢ Q Total. s daily | | | | mum. mum. mean ee Seas | al eee Ee (Cie 27a SEE °F. Nov. 4,07 | Rabbit.... Le) ee O ON es O20) 20 1 0 Lo |uicidhasiodwosl dadianice tial Wes cee eee INOW UAW Sac Waasoen- OES OME Oe Os 20 0 1 1 eee eee Beroea cs . - Apr. 10,08 | Bovine Sa OF On Or Os s0 2 1 3 83.0 47.0 68. 84 AMT A OSHEer Coe eee Gn On On Os SaOn nO 1 3 4 83.0 47.0 68. 98 NFO Vey Ne nCKOye Seana OM ON OAL ON Oy > @ 1 it 2 83.0 47.0 70. 07 JuMe "6; 08) | esd ose ae o- FORO} On| Onno 4 il 5 91.5 69.0 80. 52 Tune OSs dOse se see 24 On nOn ie Om Gain) 8 15 23 91.5 69.0 80.57 Junews 08) fe doOne ase 1A OR One 10" ON ex0 5 if 12 91.5 69.0 80.39 June Oy 08) |2e donee e=- 2A OF) {On 0 Ont a0 Wel sachet 2 91.5 69.0 80. 55 Nov.10,08 | Quail....-- ABN Oe Ot Osi Oa o 0 2 2 82.0 34.0 59.15 Nov.25,02 | Rabbit Pi fal Viale eh ba! | ada 4 Oe AI be ll oe 24 83.0 17.9 58.34 Dec. 29,09 | Chaparral GaletON | Os Os Os a0 3 2 i 87.0 17.0 61. 62 cock. Total) sr vse: |< aggyel al oats lS ae 26| 33 841.0 noc wll kee i o = Male. Q= Female,
THE RABBIT TICK. 95
The adult (Table XX VIII).—The longevity of adults of this species is probably equal to that of any other ixodid tick. In a tube which contained a lot of about 24 adults which molted from nymphs shortly before September 29, 1909, the last individual, a female, died May 10, 1911, having lived at least 588 days. A male in another lot which molted to adults between February 22 and March 29, 1910, lived for 403 days. In a third test a female in a lot which molted between March 23 and April 4, 1910, died on May 10, 1911, after a period of 401 days. One male in a lot of about 6 males and females which became adult April 15, 1908, lived for 395 days. The longevity of several other lots of ticks upon which the date of molting was recorded ranged between 109 and 355 days. These lots became adult in the spring and early summer months. A longevity of from 17 to 167 days was observed in the case of 10 lots of adults collected on hosts during 1909 and 1910.
Considerable difficulty has been met with in getting females to engorge. Although males and females have attached in conspicuous places on the ears of tame rabbits, we have failed to observe them in copulation. A small female dropped in 17 days, but the only female which attained full size required three weeks for engorgement.
The last individual, the engorgement of which 1s recorded in the following table, was placed on the host without males. Mr. George Wolcott, who observed this engorgement, found that it attached in less than half an hour. It remained for at least three weeks before any appreciable engorgement took place. In the last three days engorgement was very rapid.
TaBLe XXVIIIT,—Engorgement of females of Hemaphysalis leporis-palustris.
: Female | Period Adults applied. Host. dropped jof attach- Size engorged. | engorged.| ment. | | Days. NE ee ee eee ee ee Rabbit....| July 25 17 | 6 by 3.5 by 2.5 mm. oe RE eg § EN A Oe ee ee | ee OGk 2 2. | July 29 21 | 10 by 6 by 3 mm. a i SE ee ee Ae do.. Aug. 3 26 | Scratched off. rt ES ee he ee ee ee ee | Feb. 18 | 35 | Fully engorged. | LIFE CYCLE.
This tick may commence to oviposit as soon as the fourth day after leaving the host. The largest number of eggs deposited by an individual was 2,240. The eggs have been found to hatch in 22 days. A total effective temperature of at least 902° F. is required for incuba- tion. Larve have been found to live 258 days. They may engorge and drop in 5 days after attaching to a host. Molting of larve may begin in 18 days. A total effective temperature of 463° F. appears to be required for the transformation to nymphs. Nymphs may live
96 LIFE HISTORY OF NORTH AMERICAN TICKS.
for 342 days. They may engorge in 4 days after attachment and begin molting 13 days after dropping. A total effective temperature of about 486° F. is required to produce this transformation. Adults may live for 588 days without food. Both sexes have been found together in abundance on wild hosts, but copulation has not been observed in ticks reared experimentally. Females may drop engorged in 17 days after attachment to a host.
The three stages of the rabbit tick have been taken from hosts in nature during all seasons of the year. We have found the immature ticks in great numbers on ground-inhabiting species of birds in the fall and winter; they may, however, be equally numerous in the
summer. ECONOMIC IMPORTANCE.
On account of the fact that this tick confines its attack to rabbits and wild birds, it is of no importance economically. In a few instances the species has been known to become so abundant on wild rabbits as to render them so weak that they could be easily killed by their enemies. Mr. W. V. King killed two snowshoe rabbits (Lepus baird:) at Florence, Mont., on April 3, 1910, which were infested with 1,033 ticks. Many of these were fully engorged females. The large number of specimens found on quail and meadowlarks leads us to believe that in some cases the young of these hosts may be killed by tick attack.
NATURAL CONTROL.
The bird hosts of the rabbit tick undoubtedly destroy a considerable number of them, although they also serve as disseminators of the species. As has been stated, rabbits have been obServed by us to devour engorged ticks and no doubt some specimens are injured by the scratching of this host. The smaller birds, such as sparrows, and certain reptiles and batrachians, are also probably of some importance in the destruction of this tick. It is known that this species is parasitized in the nymphal stage by a chalcidid. This parasite (Jzodiphagus texanus), the first recorded as having been reared from a tick, was described by Dr. L. O. Howard (1908) from individuals reared at the tick laboratory from engorged nymphs collected by Mr. J. D. Mitchell in Jackson County, Tex. A single specimen in each of two different lots of engorged nymphs was found to be parasitized by this insect. One of these lots was collected March 10, 1907, on a cottontail rabbit and the other May 1, 1907, ona jack rabbit. Subsequent collections in that locality have failed to reveal other parasitized specimens.
Bul. 106, Bureau of Entomology, U. S Dept. of Agriculture PLATE VII.
Hzemaphysalis leporis-palustris: Fig. 1—Unengorged larva. Fig. 2——Unengorged nymph. Fig. 3.—Engorged nymph. Fig. 4.—Engorged female. Fig. 5.—Partially engorged female (balsam mount). Fig. 6.—Male (balsam mount). Hemaphysalis chordeilis: Fig. 7—Male, dorsal view. Fig. 8.—Male, ventral view. Fig. 9.—Engorged nymph, dorsal view. Fig. 10.—Engorged nymph, ventral view. (Original.)
LIFE HISTORY OF NORTH AMERICAN TICKS. 97
THE BIRD TICK. Hzmaphysalis chordeilis Packard.
The common name of this species is applied on account of the fact that birds are its principal hosts.
DESCRIPTIVE.
Adult (Pl. VII, figs. 7, 8)—Males from 2.8 by 1.5 mm. to 2.9 by 1.6mm. Scutum light gray in color, shading into amber anteriorly; marginal strip bluish white; legs and capitulum amber. Females, unengorged, from 2.8 by 1.4 mm. to 2.9 by 1.8 mm.; engorged, about 9 by 6.6 by 4 mm.; reddish brown in color when unengorged, scutum without markings.
Nymph (Pl. VII, figs. 9, 10) —Unengorged, 1 by 0.65 to 1.4 by 0.72 mm.; light brown in color, scutum darker; engorged, about 2.43 by 1.79 mm.; color dark gray. Capitulum 0.217 mm. in length (from tip of palpi to base of emargination of scutum); scutum 0.446 mm. long by 0.447 mm. wide.
Larva.—Unengorged, from 0.552 by 0.402 to 0.574 by 0.430 mm.; body ovoid, yellowish brown; engorged, from 1.4 by 0.8 by 0.6 mm. to 1.5 by 1 by 0.6 mm.; abdomen slate color. In most cases three distinct longitudinal white lines are to be seen on the dorsum; shield very dark brown, almost black posteriorly, shading to a pale yellow-brown anteriorly. The legs and mouthparts are translucent yellowish brown. Capitulum 0.125 mm. in length (from tip of palpi to base of emargination of scutum), scutum 0.240 mm. long by 0.308 mm. wide.
Egg.—No eggs of this species have been seen by us.
HOST RELATIONSHIP.
The type host of this species is the nighthawk. The species has a comparatively wide range of bird hosts. Those species which are more or less ground-inhabiting seem to be more frequently infested. The immature stages of this tick are frequently found in large num- bers, usually attached to the heads of the hosts. They are very fre- quently associated on the hosts with the immature stages of Hema- physalis leporis-palustris. The following birds have been found to act as hosts: meadowlark, jackdaw, red-winged blackbird, marsh hawk, quail, and domestic turkey. Mr. Banks mentions having seen a nymph, probably of this species, from the killdeer. The examina- . tions of birds in Texas indicate that the meadowlark is by far the most commonly infested host. We also have a fairly reliable record of three adults of this species having been taken from a prairie chicken in Texas. As has been stated, the ticks are usually found to attach on the top of the head. They are also found around the eyes and ears and occasionally under the bill.
21448°—Bull. 106—12——7
98 LIFE HISTORY OF NORTH AMERICAN TICKS,
GEOGRAPHICAL DISTRIBUTION.
The type locality for this species is Milton, Mass. Specimens have also been taken at Norwich and Taftsville, Vt. Most of the other collections were made in Victoria and Refugio Counties in Texas by Mr. J. D. Mitchell. We have one authentic record from D’Hanis, Medina County, Tex., and one of the authors (Hooker) collected larvee and nymphs which he thought were this species at Grand Cane, La., and Hawthorn and Quincy, Fla. It is very probable that this tick has a wide range of distribution, but owing to the fact that little collecting has been done upon birds in other localities, the range of the species is not fully known.
LIFE HISTORY.
Little has been published on the biology of this tick. Hooker (1909a) reports the finding of molted larval skins attached to the head of a meadowlark. These were associated with engorged larve of this genus and it was thought that they might be exuvia of the bird tick. : The egg.—Owing to the difficulty in securing engorged females no records have been made upon preoviposition and oviposition periods. The number of eggs deposited by this species has not been determined. Dr. Philip B. Hadley, of the Rhode Island Agricultural Experiment Station, kindly sent Mr. Nathan Banks a large number of larve which hatched about August 15 from eggs deposited by a number of engorged females collected on turkeys at Norwich, Vt., June 28, 1909. These larve were forwarded to us at Dallas, Tex., by Mr. Banks.
The larva (Tables XXIX—XXX).—The longevity of the larva of this species has not been definitely determined. Larve of one lot which hatched about August 15 lived at least 39 days. At the end of that period they were placed on hosts.
As is indicated in Table X XIX, larve have been engorged on rab- bits and guinea pigs. Two attempts to engorge them on chickens failed, though a few were found to attach. Attachment was found to take place very soon after the larve were applied, usually within 5 to 30 minutes. Dropping began as soon as the fifth day after attachment. The longest period of engorgement observed was 12 days. The weighted average time from application to dropping in the case of the 33 larve engorged was 7.5 days. 3
THE BIRD TICK. 99
TaBLE XXIX.—Engorgement of larvx of Hemaphysalis chordeilis.
Larve dropped engorged—days | Date following application. | Total | larve Host. x 4 | nme | State of engorgement. applied : dropped. | Bil Gee ouly- 8 OM TF | 12 1909. Beep. «| sabbit....2--- Si S| RP 2 OP ah O | 0} 21 | Fully. Peiicedes | HOne = 255 2S TOs Ob Onl Or Orb Ol 6-1) (0: 0 | Sept. 17 | Guinea pig 7 al ees Re ee Descent Sf teretiow | 2 | Fully. mt, 18 f Hen. ....2.;.- Cr Of 0.) 0) 87°04 081.6) 0 : Sept. 22 | Rabbit...:..-- MG ek dl mh Ue Sa i US ES St 3 | Two-thirds to fully. Sept. 24 |..... G0. 25 =.4-- my 81 OF Oo) 2) sf 2). ), 2 7 Two-thirds to fully. Total...| 225 soefeoe ie | il = ee | 33
At a mean temperature of 79.05° F. molting began on the four- teenth day after dropping. When the mean temperature fell to 53.98° F. 76 days elapsed before molting began. This and the other long molting period given in the table were recorded on larve col- lected from wild hosts, and although the state of engorgement of the ticks was not recorded, there is little doubt that they were not fully engorged. This would tend to lengthen the molting period as has been found true in all observations made by us on this point. A total effective temperature of 505° F. appears to be required for this transformation.
TABLE XXX.— Molting of engorged larve of Hemaphysalis chordeilis.
Temperature from Engorged larve molted—Days following dropping. dropping to date first tick molted.
Date Num- oe poe Si as a ep o5 engorged | Host. | ber of |_| | a dropped larve. | | Total Maxt: | Mini Aver- : . ee ‘ axi-| Mini-| age 14, 15)16 17/18 19) 21 96 bar fag 67 |76 | 92 ere ernae lscecet a ae heed ‘ mean. ETS. het EE STU RD ke ES A a2 1909. Sean ome i Say: Nee
Sept. 12] Rabbit.| 6 go oe ee et ie. Pee OPA [Bos Wee ae 3 | 98.50 | 59 79. 84 ee 200.00). 9) Ate. -|ou Be Tete desk bth c 6 | 96.50 | 59 79.05 Sept. 14 |...do CRASS, iy Rie pt TE 4 ties pis feattey: let hogareg, 1 te 1 | 95.50 | 56 77. 28 Sept. 17 |...do 2 5 ee ot es ae es ee ASE oS eR 21 95.50 | 56 76.75 Sept. 25 |...do 1 Ae U2. IEC EAS SES yg EA ER a 1 | 92.50 | 51 72. 38 Sept. 30 |...do 1 alg eae (ee ea PA Sa) 1 | 92. 50 | 51 72.77 or) 2 |. --d0 2 a is | sg CE Ee BG ER ee eae 2 | 92.50 | 52.50 | 73.80 Oct. 3 |...do 3 des | ON celics es Hi Ber 1/92:50/52 | 72.88 mre 16 |..2....- 6 cles el Cis Oe ES tae OS a 2| 79 20 | 53.98
Nov. 25 | Meadow- lark pg See (479 Pee ee ae ey am ek ea ee 4} 4 | 79 20 52. 96 Total..| 36+ |...| | | “Taw See | > Seeker
1 Three of these molted before Jan. 31, 1910, and one on that date.
The nymph (Table XX XI).—On account of the sparsity of material at hand, our records on the longevity of nymphs are fragmentary. One nymph which molted from a larva about January 22, 1910, was alive on April 6, 1910, when it was put on a host. This individual had lived 74 days, which is the longest period recorded by us. One nymph which molted February 15, 1910, died 16 days later. Two
100 LIFE HISTORY OF NORTH AMERICAN TICKS.
other lots lived from 16 to 55 days, at the end of which time they were put on hosts.
Nymphs were found to attach readily to a bovine host very soon after being applied. Attempts to get collected nymphs which were partially engorged to reattach to cattle and guinea pigs were not successful. - Similar results were obtained when attempts were made to attach to rabbits and cattle nymphs which had very recently molted from the larval stage. Inthethreelots of nymphs the engorge- ment of which is recorded in the accompanying table the shortest period of engorgement was 5 days, the longest 8 days, and the weighted average 6.9 days. All of the specimens were fully engorged when they dropped.
TABLE XX XI.—Engorgement of nymphs of Hxmaphysalis chordcilis.
Nymphs dropped—Days
N following application. Total Date nymphs applied. Host. lee number 5 dropped. 5 6 7 1909. INOVeSeeinee sash = saad sc een eee oe Bovine Ai eee ek re [PR ae ror 3 1 INO VA SU Sos canoes coe eS ne Se eee lee dose 1A IR ROR | he Be coee ne | ye 2 2 IN OVE 285/29 So caslstonimnaiee mc os sees ees leeS GOleaas 5 1 D thera Sperry es ene
The shortest molting period for nymphs in the 13 cases observed was 26 days. During this period the mean temperature was 68.05° F. and the total effective temperature 651° F. The longest molting period was 186 days at a mean temperature of 60.54° F. The lots of collected individuals varied from one-tenth to fully engorged. None of the specimens under ene-half engorged was observed to molt to adults. The temperatures given are those recorded at the Dallas laboratory from the date the ticks were collected to the date when the first tick molted.
The adult—Of a lot consisting of 4 males and 3 females which became adult between May 5 and 10, 1910, 2 individuals of each sex were placed on hosts, 2 males and 1 female being kept for a longevity test. One male and the female died on August 18, 1910, having lived about 100 days. The last male lived until March 11, 1911, or a period of 305 days. A female in another lot was found to live between 131 and 166 days after molting, and in a third lot a male lived between 97 and 127 days. Unengorged adults remain inactive for long periods when kept in a tube, and it is sometimes difficult to induce them to crawl. One female which was fully engorged but not fertilized lived 172 days, no eggs being deposited.
A male and a female were placed on a bovine April 30, 1910. The female was found to be attached when examination was made 6 hours later. The male failed to attach as did also two other males
THE BIRD TICK. 101
applied several days afterwards. The female, however, began to fill with blood and 19 days later dropped rather well engorged. This female did not deposit eggs but lived 172 days, as noted above. Attempts to get adults to attach to a hen were unsuccessful.
No observations have been made on mating, nor have the periods of preoviposition and deposition been determined. The number of eggs deposited has not been determined as yet.
LIFE CYCLE.
Larve may live for at least 39 days and probably much longer; they engorge in from 5 to 12 days and molt in the summer as soon as the fourteenth day after dropping and as long as the ninety- second day after dropping in the winter. A total effective tempera- ture of 505° F. is required for this transformation. One nymph lived for at least 74 days. Nymphs may become engorged in 5 days during the last of November. Molting to adults occurred in as short a period as 26 days after dropping and during the winter a molting period of 186 days was recorded. A total effective temperature of 651° F. appears to be required to produce the nymphal molt. Males may live 305 days and females as long as 131 days.
Most of our collections have been made between November and April. During this period all stages have been taken on wild bird hosts, the larve and nymphs being very abundant. No doubt they are present on hosts in Texas throughout the year. In Vermont, where the species has appeared as a pest to turkeys, adults and imma- ture ticks were found in abundance in June.
ECONOMIC IMPORTANCE,
The bird tick has attracted attention as an economic species only in a few instances. In 1906 a specimen was received by the Bureau of Entomology from Taftsville, Vt., with the statement that it was found attacking a turkey. This species was not again heard of as a pest until June, 1909, when the attention of Dr. Philip B. Hadley, of the Rhode Island Agricultural Experiment Station, was called to a flock of young turkeys which were being killed by this tick at Nor- wich, Vt. The parasite appeared on turkeys on two farms in that locality. Dr. Hadley states that on one farm 40 out of a flock of 46 turkeys died before the ticks were finally destroyed by hand picking. Numerous adult and immature ticks were found to be attached to the hosts, principally on the necks of the birds. Dr. Hadley informed us that apparently none of these ticks was present in the vicinity of Norwich during 1910.
It is doubtful if these ticks ever become so numerous on wild birds as to cause their death, though they frequently appear in great num-
102 LIFE HISTORY OF NORTH AMERICAN TICKS.
bers on quail and meadowlarks. Turkeys ranging over fields where wild birds are numerous are quite likely to become infested and thus bring the ticks into the poultry yards.
NATURAL CONTROL.
On account of the fact that this appears to be principally a bird- infesting species, there is undoubtedly a large mortality due to their destruction by the host.
ARTIFICIAL CONTROL.
This species has not been studied sufficiently to warrant any statement regarding control. It has been reported by Dr. Hadley that the ticks are exceedingly hard to kill by the application of such substances as kerosene and lard. He states that hand picking was the only method of control found to be effective against the ticks where they appeared as a pest on a farm at Norwich, Vt. A knowl- edge of the relation between the wild bird hosts and domestic turkeys may possibly suggest some preventive measure.
Genus RHIPICEPHALUS Koch.
Only one species of the genus Rhipicephalus occurs in the United States and that only in the extreme southern part of Texas. The genus, however, is a large one, as many as ten species being recorded by Howard (1908) as occurring in Africa alone. The members of this genus are also of considerable economic importance, five species being known to be active agents in the transmission of African coast fever, a highly fatal disease of cattle. One of these five also transmits biliary fever of horses, mules, and donkeys. A sixth species transmits ovine piroplasmosis in southern Europe, while in the Old World a seventh, the species which we have studied and consider here, transmits canine piroplasmosis.
Most of the species drop to pass their molts, but two, Rf. everts: and R. bursa, pass the first molt while on the oe
Cipeceione on the biology of the African species have been published by Lounsbury (1900b, 1905), Theiler (1905, 1909), and Howard (1909). Observations on R. bursa have been reported by Motas (1903).
THE BROWN DOG TICK. Rhipicephalus sanguineus (Latreille) (teranus Banks).
The common name of Rhipicephalus sanguineus (brown dog tick) is taken from its color and the fact that the dog is its principal host.
THE BROWN DOG TICK. 103 DESCRIPTIVE.
Adult (Pl. VI, figs. 13-17).—Males from 2 by 1.25 to 3 by 1.5 mm. Females, unengorged, 1.5 by 1 mm. to 3 by 1.75 mm.; engorged, 6 by 4 by 1.5 mm. to 11 by 7 by 4.5mm. The males and females are reddish brown, without markings, the legs being somewhat paler.
Nymph (Pl. VI, fig. 12)—Unengorged, about 0.94 by 0.57 mm.; engorged, 2.5 by 1.5 by 1 mm. to 3.5 by 2 by 1 mm. Color, unen- gorged, reddish brown; engorged, dark gray, some with a pink tinge and many whitish due to the engorgement of lymph; smooth, shining. Capitulum 0.244 mm. long (from tip of hypostome to base of emar- gination of scutum); scutum 0.451 mm. long by 0.462 mm. wide.
Larva (Pl. VI, figs. 10, 11)—Unengorged, about 0.457 by 0.328 mm.; engorged, about 1.5 by 0.88 mm. Color, unengorged, light brown; engorged, dark gray; capitulum 0.116 mm. long (from tip of hypostome to base of emargination of scutum); scutum 0.212 mm. long by 0.301 mm. wide.
Egg.—The average size of 10 eggs was 0.43 by 0.37 mm.; ellip- soidal, dark brown, shining, smooth.
HOST RELATIONSHIP.
Although this tick infests principally the dog it appears to attach to numerous hosts, among which the following have been reported: Fox, and ‘other canines, cat, ox, horse, hare, dromedary, camel, sheep, goat, birds, and also one or two species of reptiles.
In extensive collections made by agents of this bureau in Texas and Mexico, however, the species has been taken from the dog only. Newstead reports that in Jamaica it is common on the ox as well as the dog and that it was also found on the horse. In one instance two slightly engorged nymphs attached between the fingers of one hand of _ one of the authors after he had been collecting specimens from dogs.
In regard to the position of attachment, Christophers, as well as the writers, has observed that the adults frequently attach to the inside of the dog’s ears, even deep down in the meatus. Christophers, Nuttall, a correspondent of Newstead, and the writers have observed that they frequently attach between the toes and that they may be found there in clusters of 3 or 4. The writers have found the females to engorge to repletion between the toes of puppies. This position is readily accessible to the ticks and infestation may occur without being suspected, as even the engorged females are often obscured from view. Many larve and nymphs of this as well as other species attach and engorge in the little pocket on the posterior border of the ear. In the immature stages it appears to prefer to attach in the long hair on the neck rather than in the ears, the ticks frequently being found in cluster of a dozen or more. All three stages may, however, attach to almost any part of the body.
104 LIFE HISTORY OF NORTH AMERICAN TICKS. : GEOGRAPHICAL DISTRIBUTION. (Fig. 6.)
This species is probably the most widely distributed of all the ticks, at least of the ixodid ticks, even though largely limited to the
Fic. 6.—The brown dog tick, Rhipicephalus sanguineus: Distribution in the United States. The large dot; show loc.lities where the species has been collected in our investigation. The small dots indicat
the probable distribution of the species. (Original.)
Tropical and Subtropical regions. Portugal is the type locality of the species. In Europe it is also recorded from France, Italy, Sicily, Corsica, and Roumania; in Africa from Egypt, Algeria, Tunis, Nubia, Abyssinia, Zanzibar, German East Africa, Portuguese East Africa,
THE BROWN DOG TICK. 105
Transvaal, Natal, Cape Colony, Madagascar, German Southwest Africa, Kamerun, Togo, Congo, and Senegal; in Asia from Arabia, Persia, Malay Archipelago, India, and China. It has also been reported from Australia, the Philippines, and the Hawaiian Islands. In this country it has been commonly taken in southern Texas as far north as Jackson County and San Marcos in Hays County, and as far west as Del Rio. The species has been collected at several points in Mexico as far west as Torreon, in Panama, Colombia, Guiana, and Brazil, and undoubtedly occurs in all of the intervening countries. It occurs throughout the West Indian Islands, having been reported from Jamaica, Haiti, Antigua, and Dominica. Ticks from the West Indies, including Cuba, Haiti, and Curacao Island, have been referred by Neumann to R. bursa.
LIFE HISTORY.
Observations on the biology of this tick have been made in India by Christophers (1907), in Jamaica by Newstead (1909), and in Texas by Hunter and Hooker (1907), and by Hooker (1908).
Theegg (Table XX XII).—Christophers reports that engorged females after dropping from the host at once proceed to crawl away, climbing upward sometimes to a height of over 15 feet from the ground, into cracks and crevices. He states that it often crawls into cracks so narrow that it becomes firmly wedged in. We also have observed that there is a decided tendency for the females to crawl upward. It appears certain that the majority of females drop and deposit eggs in or near the kennel or sleeping place of the dogs.
Temperature has a very marked influence on the preoviposition period. InJuly and August at a mean temperature of about 85° F., oviposition began on the third day after dropping, while ticks which dropped on November 1, 2, and 3, did not begin to oviposit until the fifty-fourth, sixty-ninth, and eighty-third days, respectively, after dropping. The mean temperature during these periods was about 62° F.
The period of deposition is also decidedly affected by the tempera- ture. This period varied from 8 to 67 days. The cool weather tends to produce intermittent deposition. The largest number of eggs re- corded, 2,616, was deposited within a period of 11 days, beginning on September 5, by a tick which measured 10 by 7 by 4.5 mm. The large daily deposition and the short period required for oviposition during warm weather are noticeable characteristics of this species. Of the 12 cases in which oviposition was recorded the smallest number of eggs was 360. This was in November. The average of the 12 females was 1,601 eggs. Death usually takes place between the first and fourth days after deposition is complete.
106 LIFE HISTORY OF NORTH AMERICAN TICKS,
The minimum incubation period recorded was 19 days. This record was made on eggs deposited on August 21 and kept at a mean tem- perature of 83.5° F. An effective temperature of 774° F. appears to be required for incubation. Christophers states that eggs hatch in 3 or 4 weeks.
TaBLeE XX XII.—Jncubation and larval longevity of Rhipicephalus sanguineus.
IN THE LABORATORY.
Temperature during incu- bation.
. Minimum Eggs deposited.| 42thing | incubation | All larvee dead. | Larval lon- gan. aa gevity. Aver- Peewee Maxi-| Mini-| age Total mum.|mum.| daily “« oa mean es Days. Days i 5) a? OPE Wa ede Mar. 31, 1908..... May 10,1908 AVS We ade Sum aseie oe sec Meee ee ee 85.0 | 47.0 | 69.00 |1, 066, 37 Apr. 18, 1908... - May 26, 1908 39 July 7, 1908. 42 | 87.0} 47.0 | 72.18 |1, 138.25 Apr. 20, 1908....| May 27,1908 5 el BE cssaoccorcccda) Eeabtecmcmes 87.0] 47.0 | 72.38 |1, 082. 25 Apr. 22, 1908....| May 26, 1908 35. hilt: cance ee re A lakes eae oe 87.0} 47.0] 72.05 | 986.25 July 7, 1908....-.- July 27,1908 21 Oct 7,01908eee-e 72 | $5.0} 74.0] 83.99} 860.50 July 29, 1908....- Aug. 17, 1908 20 | After Sept. 10, 1908 3e eet a 24+ | 99.0] 73.0] 86.50 | 870.00 July 31, 1908..... Aug. 19, 1908 20 | Sept. 30-Oct. 26,1908) 2-66 42-68 | 99.0] 73.0 | 86.70 | 874.00 Aug. 2,1908....- Aug. 22, 1908 21 Sept. 28, 1908 - - - 37 | 99.0] 73.0 | 86.26] 908.50 Aug. 21, 1908....] Sept. 8, 1908 19 | Nov.13-26, 1908. 66-79 | 97.5 | 75.0] 83.73 | 774.00 Aug. 25, 1908....] Sept. 12, 1908 AOE. i Seer Gore 8 250 62-75 | 97.5] 74.5 | 88.90] 777.20 Aug. 26, 1908....| Sept. 14, 1908 740) (ee GOssecetgee 60-73 | 97.5] 74.5 | 83.60} 812.45 Oct. 21, 1908. ... - - Mar. 11, 1909 142 After Apr. 24, 44+ | 85.0] 17.0 | 60.88 |2, 314.00 O09 cae ene Sept. 20; 1910. -..| Nov..12?, 1910) | 54 (abowt)-| Feb. 20, 1911-22) 100\(@bowt) ||s2.524_|2-2 2 cole Sole ee OUT OF DOORS. Apr. 13-26, 1906 .| May 27, 1906 45 Aug. 15, 1906... - 80 | 93.0] 41.5 | 69.08 |1, 173.60 Apr. 28,1906....| May 30, 1906 Chi Sse ose cahaocet Sern oeSackoes 93.0] 42.0] 71.72 | 947.76 Before May 4,1906| June 5, 1906 Soe ieee een ae Ss $e) peor See One | MEMoren| ence) sect esicece =. May 17, 1906..... June 9, 1906 7 a RUE Sa IS CF on) [Oh SO WD OE 93.8 | 59.2] 76.90] 813.60
Thelarva (Table XX XIIT).—The longevity of larvee in summer under the most favorable conditions was 80 days. Several lots are recorded, however, in which the longevity was much shorter, the average life being not far from 2 months. The last individuals of a lot of larvee from eggs deposited from August 4 to 6, 1907, and which com- menced to hatch August 25, died between January 3 and 10, 1908, thus having lived between 131 and 138 days. Christophers states that in nature the larve collect near the bottom of walls and wait for a dog to brush against the spot.
Engorgement took place in as soon as 8 days; the greatest num- ber dropped from the third to the fifth days, and all dropped before the seventh day. Christophers found larve which he placed upon a dog to engorge and drop in from 3 to 4 days.
Ae a Eps gk te
THE BROWN DOG TICK. 107
TaBLE XXXIII.—Engorgement of larve of Rhipicephalus sanguineus.
Date larve applied. | Host. : i | number 1} 2| 3] 4{ 5] 6] 7| 8 | © |4rpped
' : ees bs Oct. 3,1907..............| Bovine... 0] 0] 51] 1388] 6] 2] Oo} o| of} 197 epi | Ee ae eee eee 0 0 0 58 18 2 0 | 0 | 0 | 78 Sune &, 1908..........-..|---. do...) 0) 0 | 25] 85] 31] o|] 0 | o| o| 141
At a mean temperature of 82° F. larve which dropped engorged on June 18, 1908, commenced to molt on the sixth day, while ticks which dropped October 6-8 did not commence to molt until the twentieth and twenty-third days. An effective temperature of 235° F. was required. Christophers states that 9 or 10 days are required for molting.
The nymph (Tables XXXIV, XXXV).—In order to determine the longevity of nymphs, a large number which molted September 30 and 31, 1907, were kept in a tube in the laboratory on moist sand. On March 5, 1908, 12 were alive, while on March 28 only one survived. On April 1 the remaining tick was found to be dead. Thus all of this lot were dead in 6 months from molting. Four of 6 nymphs which molted June 8 and 9, 1908, were dead August 3; on August 10 one was still alive, but on August 20 the last one was dead. Thus in summer nymphs lived but two and one-half months at the longest. Of a lot of 23 nymphs, slightly to one-third engorged, that were collected on dogs, October 29, 1910, 2 lived until April 5, 1911, or 158 days.
Engorgement was found to take place as soon as 4 days after attach- ment. The greatest number dropped on the fifth and sixth days; all were engorged and had left the host by the tenth day.
TaBLE XXXIV.—Engorgement of nymphs of Rhipicephalus sanguineus.
Nymphs dropped engorged—days following application. Total gen Host. | ; ; ' } number 1 | ah Oe ae 7" Ex See Se EE. Sew nh ag Ss Re Ope a Be, Pe ee es Pees | | Nov. 7, 1907...... Bovine Pel et wt at el TT el 16 July 13, 1908......|...do......| 0] o| o| 3{ 10| 15] 5] 5] 1] Oo | 39 i
In summer, when the mean temperature was between 84.65° F. and 85.42° F., molting has been observed to take place as soon as the twelfth day. A total effective temperature of 500° F. is required to produce this molt. The molting period of nymphs which form males appears to be the same as for those which form females. Christophers found 15 days to be required for molting.
108 LIFE HISTORY OF NORTH AMERICAN TICKS.
TABLE XXX V.— Molting of engorged nymphs of Rhipicephalus sanguineus. [¢=Male. 9=Female.]
Engorged nymphs molted—days following dropping. Date engorged TET st | CLE Gc EEE ae ee
nymphs dropped. ber | 12 | 13 | 14] 15 | 16 | 47 ie 20 | 23 | 26 | 27 | 29 |53/56 Sept. 22, 1907.......-. DOP. =r A (De et eee pall) Cc | ee Se S2 eee So fore, | {Mee Bee ee ee int Sl Oct. 27, 1907......-..|... do ys VGegaeee eee ee Se AE ace he reg heel Vee ea Nov. 11, 1907.-.......| Bovine... Rie aie een bee een pete ea Jans Pe heel es fi mee Nov: 12, 1907.........|_..dos...- ae ere I I Me FS ena eee ee el © Apr. 22, 19081........| Dog..... Gp Ege enee Pek ede ca Eg [ayia er se 1 6 a) 2 July 17, 1908......... Bovine. a asig| Ne. Tolle eae i July 18, 1908.......-. ao. &: foe: 38 35 hala lah dec onleea elle aes July 19, 1908......... aoe 155} OURS ISG here Leclaaeal. sa be al Pale ale July 20, 1908......... Hie aes Bledel lled laces eer SE. Cea i flee July 21) 1908......... Reda 3/1919 el astacske foo aS Aug. 17, 19082....... Dog... 100 |--..|---{44 5138) 281 59|}19|----|---- ocak cael ae (33| 23| 63 33/43} 128 AUIS LOSI rae wee Se Ob gee 100 “CA Ol Be Mallee 49] 39 Tete eae: Se (ere ---|-0= Nov. 29, 1909.........|...do..... Ct oe ee WE ela ame Re RS st ele Aye hy ae Total. ODI labs | ae Smeal ede lL eile Spelt, ete | cue a Sa
Engorged nymphs molted— Number Temperature from
days following dropping. molted. dr PE first Date engorged Num- | i nymphs dropped. Host. ber. : ; cs = = Ret Ge = 2s leeo heater pli 3 =) = Os 57 | 58 | 59 | 73 |122)125)127/129) Pt ls g g 2 @ Nh = ll hap 9 5A S 3) S SI A > SU SHE’ fel = |< un pi ie i; Sept. 22, 1907....- Dovse=- Dass se Seu eee erate eee 1} od [48.223 eee Oct 2%, 190%eeea- 3 |= =e Oss. Doe Sst eager Seer] ae | eee ates eerie | eres 2) 2 Sa ee Nov. 11, 1907..... Bovine Salahiehl ACH Sala eee Ce ee | i ee ees PS INOVAIEZS 190 Tes |e Osea Go VO ES sO MORSE alesse at ce A) 6S. noe a eee oe ee Apr. 22, 19081....; Dog....- 1S eee lioeee all eh ate fe ees eo ooees ecacder 11 | 86.0] 47.0] 70.39 July 17, 1908...... Bovine.. Hi oes 3 he eo [ee Borel cea | erese 2 1} 3 | 95.05] 76.5.) (8456e MUly 18; 1908 eeeec| a dOenaas IO} See eect be er lees eee oe ee | Ree 6 4/10} 95.0] 76.5 | 84.70 Daly 9, 1908sssec5 | -d0lee=- 157 |S sale sec Se aes eee eels ale 16 8| 14] 95.0] 76.5] 84.69 July,20) 1908: 2-2-5 |69-G0:2=-- Oy ee Sees ge |ecsel| Sae eve Sen See 3 1] 4] 95.0] 76.5] 84.92 Stily; 21; 1908 esse GO: ose ai | ee as Sst | (Ss PSE ees eve et oo Fame) 2| 2) 95.0] 77.0 | 85.42 Aug. 17, 1908 2....| Dog.-.--- LOO) osc |B se onl sealer See eee) tet 40 | 67 | 96.0} 75.5] 83.90 Aug. 18, 1908 8....]...do..... LOOK Fes see sue) | Secell aexel eyelet ve cell are) 33 | 53 | 9350} 75.5 | (Saeag Nov. 29, 1909. ...-|--- doko: GAs eS aa ee onal aoes OM [Prosser ee eee eee TZ) 9250°)} 205001) sasam Total 322 |. 67 OG! 19N | 2 55] cee | eee
1 Collected at Brownsville, Tex. 2 Collected at Brownsville, Tex.; 27 of these nymphs were parasitized. 8 Collected at Corpus Christi, Tex.; 40 of these nymphs were parasitized.
The adult (Table XXX VI).—Of 163 adults which were observed to molt from nymphs, 96, or 58.9 per cent, were females. The greatest adult longevity observed by us was between 204 and 214 days. This record was made on alot of 13 males and 15 females which molted from nymphs September 1, 1908, and were kept in a tube on moist sand in the laboratory. On March 24, 1909, or after 204 days, a male and a female were alive. These were both dead on April 3, 1909. Other specimens which became adult in early September were found to live nearly as long as the lot above referred to. Several lots of ticks
THE BROWN DOG TICK. 109
which became adult late in July and early in August lived from 77 to 158 days. One lot of ticks which became mature on May 18 to 21, 1908, lived about 3 months. Of a lot of 91 individuals collected on hosts on July 21, 1909, 4 were still alive December 15, 1909, having lived at least 147 days. However, a large percentage of the adults collected from dogs in the summer die within a month or 6 weeks. The longevity of the sexes appears to be about the same. We have observed unengorged adults crawling from between the cracks in floors. At Corpus Christi, Tex., they were found in considerable num- bers in the cracks of a porch floor where dogs frequently slept. Christophers reports that after molting adults crawl into straw or sim- ilar material and there await the host.
Mating, which takes place on the host, may commence as soon as the fourth day after attachment and often continues until the en- gorged female drops. The male sometimes drops with the female or detaches soon after and goes in search of another mate. In one instance a male and partially engorged female in a tube on sand were observed apparently in copulation.
On November 19, 1909, Mr. J. D. Mitchell collected a male Am- blyomma americanum in coitu with a female of this species on a dog at Corpus Christi, Tex. The mouth parts of the male were again inserted in the genital opening of the female when the ticks were put in a vial and they remained in this relation for at least fifteen minutes, when they were packed for mailing. Subsequently the female, which was partially engorged, deposited fertile eggs.
Fertilized females were found to engorge more rapidly than unfer- tilized ones. In one instance a female engorged in 6 days, while in several instances females remained attached for from 44 to 50 days, and even then were not fully engorged when they dropped. It is quite apparent that fertilization is an important factor in the period required for engorgement, as in the short period mentioned above the ticks mated on the fourth day after attachment, while in the ex- tremely long periods mentioned mating did not occur at all.
TABLE XXXVI.—Engorgement of females of Rhipicephalus sanguineus.
Period | f
| | Females Adults applied. Host. | dropped en- |. te 1 Size engorged. gorged. a | ment. | | Days NIE aos 2s = ots 2 a Oh Boe nes Det. .c 20 Nov. 2,1907 7 | 9.5 by 6.5 by 4mm. 0 SS Se Sg ee ee ee .do Nov. 3,1907 8 | 1l by 7 by 4mm. nets ce ee | Bovine....| Feb. 17,1908 44 I EDT aT ee Feb. 18, 1908 45 | 8 by 5 by 3 mm. a 2. SE RE eee eee) ee do.......| Feb. 23,1908 50 = ee eer cee ee ene do. Apr. 10,1908 6 | 9 by 6 by 3 mm. - S SE SE Be ee Seen, aed | oe do.......| Apr. 11,1908 7|8by5 by 2mm. a ae, 8 ellie SR ee eS eae a (ES do. Apr. 12,1908 8 | 6 by 4 by 1.5mm. Lo i Be oA RO ee ee eee Ae do. On sed 8 | Sby 5 by 2mm.
110 LIFE HISTORY OF NORTH AMERICAN TICKS.
Males do not appear to remain attached to the host after the females have dropped. If they do not drop with the females they start out in search of another mate; in this search they frequently go from one dog to another. Their longevity on the host is at least several months.
LIFE CYCLE.
Oviposition may commence as soon as the third day, and as many as 2,616 eggs may be deposited. In August eggs may hatch in 19 days, an accumulated effective temperature of 774° F. appearing to be required for their incubation. Larve may live for 131 to 138 days while waiting for a host; they may engorge in 3 days and molt in 6 days. <A total effective temperature of 235° F. is required to pro- duce this molt. During the winter nymphs may live for 6 months; they may engorge in 4 days after attaching to a host. In summer they may molt in 12 days, a total effective temperature of 500° F. being required. Adults may live as long as 204 days; they may become engorged in 6 days after attaching to an animal; fertilization takes place on the host. All stages of the tick may be found at any time during the year. However, they are less numerous after long continued drought.
ECONOMIC IMPORTANCE.
This species is perhaps the most important tick that attacks the dog. While restricted in its distribution to the Tropical and Sub- tropical life zones, it is widely distributed over the Old and New Worlds, in both of which it is the source of great annoyance to dogs. Its particular importance, however, lies in the fact that it is the active agent in the transmission of canine piroplasmosis. Fortunately this disease has not been introduced into the New World. It is, however, prevalent in certain sections of the Old World, particularly in India. The disease also occurs in South Africa, where it has been shown by Lounsbury to be transmitted by Hemaphysalis leach.
Ce ee a es ee ree ae
NATURAL CONTROL.
While no particular investigation has been made of the predaceous enemies of the species, those attacking the cattle tick undoubtedly destroy this tick also.
In 1908 a parasite was discovered which destroys large numbers of this species while in the nymphal stage. * This parasite, the second recorded as attacking ticks, was described by Dr. L. O. Howard (1908) as Hunterellus hookeri. In order to determine the percentage of parasitism, 100 engorged nymphs were collected at Brownsville, Tex., August 17, 1908, and an equal number from Corpus Christi on August 18, 1908. These were isolated in pill boxes in lots of 10 each and kept on moist sand. Of the 100 collected at Brownsville, 27
7 ty Pa 7,
THE NORTH AMERICAN CATTLE TICK. 111
were parasitized, 67 produced adult ticks (27 males and 40 females), and 6 did not produce either ticks or parasites. Of the 100 collected at Corpus Christi, 40 were parasitized, 53 produced adult ticks (20 males and 33 females), and 7 produced neither ticks nor parasites. Although a number of lots of nymphs have been collected which have shown no signs of parasitism, the insect is undoubtedly an impor- tant enemy of this tick. The parasite appears to be more restricted in its distribution in the United States than is the tick. Recently Mr. C. W. Howard has reared this an in Portuguese East Africa from the same host.*
ARTIFICIAL CONTROL.
Spraying frequently with, or dipping in a solution of one of the sev- eral coal-tar products that are now on the market should be practiced when this tick becomes a pest. It is important that the kennels or other sleeping places of dogs be kept scrupulously free from filth and that they be thoroughly sprayed at frequent intervals with some strong disinfectant. The destruction of roving and uncared-for dogs also greatly aids in the control of this tick.
Genus MARGAROPUS Karsch.
Of all the ticks those belonging to the genus Margaropus are the most important economically, owing to the part which they play in the transmission of Piroplasma and Anaplasma, which cause splenetic fever in bovines. Neumann recognizes 5 varieties of annulatus, all of which appear to transmit piroplasmosis. In addition to annulatus, we have studied the variety australis. One variety, decoloratus, is known to transmit Spirochexta theileri, which is the cause of a disease of cattle in South Africa. All of the ticks of this genus pass both molts upon the host.
THE NORTH AMERICAN CATTLE TICK.?
Margaropus annulatus (Say).
The common name of this species comes from the fact that it is the most common and important tick attacking cattle in North America.
DESCRIPTIVE.
Adult (Plate VIII, figs. 1, 6-11).—Males from 2 by 1.25 mm. to 2.4by1.3mm. Females, unengorged, about 3 by 1.75 mm.; engorged, iia 10.5 by 6 by 4.5 mm. to 14 by 9 by 6 mm.
Nymph (Plate VIII, figs. 3-5)—Unengorged, about 1.5 by 0.6 mm.; engorged, about 3 by 2.8 by 0.8 mm. Salar. unengorged, light
1 More recent studies of this parasite have been published by Wood (1911).
2 The data on the cattle tick are presented in order that its biology may be compared with that of the other ticks. For more detailed information see Bulletin 72 of this bureau. The discovery of the fact that
Dermacentor venustus conveys the infection of Rocky Mountain spotted fever has made it desirable that the above name be applied in place of that of North American fever tick, used in Bulletin 72.
112 LIFE HISTORY OF NORTH AMERICAN TICKS.
yellowish or grayish brown; capitulum and shield light reddish brown; legs pale yellowish brown; engorged, grayish blue. Capitulum 0.296 mm. long (from tip of palpi to base of emargination of scutum); scutum 0.478 mm. long by 0.455 mm. wide.
Larva (Plate VIII, fig. 2).—Unengorged, about 0.547 by 0.413 mm.; engorged, 1.5 by 0.75 mm. Color unengorged, capitulum and scutum dark reddish, legs a shade lighter, body almost colorless; engorged, light yellowish gray. Capitulum 0.148 mm. (from tip of palpi to base of emargination of scutum); scutum 0.296 mm. long by 0.341 mm. wide.
Egg.—Ellipsoidal, deep yellowish brown, shining, smooth. The average size of 10 specimens measured was 0.542 by 0.418 mm.
HOST RELATIONSHIP.
The type host is the Virginia white-tailed deer, Cervus virginianus Boddoert [=Odontocelus americanus (Erxleben)]. Of the undomes- ticated animals the deer is the only host known.
Bovines are the principal hosts of the species, but the tick also commonly attaches to horses and mules, and occasionally to sheep and goats. Only 4 engorged females have been taken by the writers from dogs, although numerous dogs have been examined and many attempts to induce this tick to attach to them have been made. Attachment to a human host very rarely takes place.
GEOGRAPHICAL DISTRIBUTION. (Fig. 7.)
Florida is the type locality. This species is limited in distribution to the Lower Austral and a very small portion of the Upper Austral and. Tropical Zones. The species occurs in greatest abundance in the humid or Austroriparian division of the Lower Austral Zone. It is known to occur only in the southern United States and Mexico, although it has been carried from this territory upon the host. The quarantine placed upon southern cattle by the United States Department of Agriculture now prevents its introduction into the Northern States.
LIFE HISTORY.
Owing to the economic importance of this species its life history and habits are better known than those of any other tick. Studies of its biology have been made by Curtice (1891), Morgan (1898), Newell and Dougherty (1906), Hunter and Hooker (1907), Cotton (1908), Graybill (1911), and others.
The egg (Tables XX XVII-XXXIX).—During the warmer months o: the year oviposition commences on the second or third day after dropping. Occasionally eggs may be deposited on the day following dropping. During the winter months the preoviposition period is
ee ee ee Pl
THE NORTH AMERICAN CATTLE TICK, MARGAROPUS ANNULATUS.
Fig. 1.—‘‘ Deposited-out”’ female with eggs. Fig. 2—Unengorged larva. Fig. 3—Engorged nymph, dorsal view. Fig. 4.—Engorged nymph, ventral view. Fig.5.—Unengorged nymph (balsam mount). Fig. 6.—Fully engorged female, dorsal view. Fig. 7.—Male, ventral view. Fig. 8.—Male, dorsal view. Fig. 9.—Unengorged female, dorsal view. Fig. 10.—Unengorged female, ventral view. Fig. 11.—Fully engorged female, ventral view. (Original.)
THE NORTH AMERICAN CATTLE TICK. 113
greatly lengthened. In one case a tick which dropped on November 20 did not begin depositing until January 25, giving a preoviposition period of 66 days. As a rule, however, the adults are killed by tem- peratures which are sufficiently low to retard deposition to this extent. The following table, which is based upon ticks which
dropped from the host, shows an oviposition period of from 1 to 3 days and a deposition period of from 8 to 16 days. The average number of eggs deposited by the 10 ticks was 3,424 and the maximum number deposited by one female was 4,547.
21448°—Bull. 106—12——-8
114 LIFE HISTORY OF NORTH AMERICAN TICKS.
TasLeE XXXVII.—Oviposition of Margaropus annulatus engorged on bovine.
Date Number of eggs deposited—days following dropping. engorged : female Size. dropped. 1 2 3 4 5 6 7 8 9 LO at 1908. : DOK YN) lone yesylon a yacebicleneeye yee 0 0] 481] 676] 754] 535] 384] 326) 194] 105 53 Aue 4 AL by 9 by 6imm 2252. See oe 0 PAL 596 857 711 708 576 | 443 166 | 264] 112 Do. Bsby v-o) Wyo oem oe 0 0} 297 560 | 457 514] 511 442 | 372 | 241 141 Dos a 225 bya yes ndMesceee ee 0 0| 494] 511 | 320] 500] 381] 272) 159 36 0 Ae. 6.) 12-5) by sib yeoeo mmm aae 0 86 | 386] 338] 427) 393 | 257] 139 57 12 10 Dots 13 Dyisibyib:> mine eee 0} 280] 420] 335! 493] 663] 540] 330] 154 96 32 Aug. 7 | 13.9 by 5 by 5mm.. 35 | 314| 431 | 425) 771 | 658|.576| 272| 2292) 76| 4 Aug.. 613 by Siby.6 mms. 2... ---- 0 OUe402i 1 481 NG124) S56ul 2i2 We oSOls 2280|) 28 17 Aug. 8 | 13.5 by 8.5 by6mm....... 0| 177] 441] 602} 729| 978| 491] 455| 245] 150] 61 Do 12°5 by, 8 byo:5 mm 3.2. 0 60 | 302) 361 | 416] 481] 353) 336] 228) 156] 148 Date Number of eggs deposited—days following dropping. Total engorged : num- female Size. ber of dropped. 12 13 14 15 16 17 18 19 | 20 | 21] eggs 1908. Aug. 3) 12) by, 7-5 by mmo. =o 30 23 4 0 0 4 B 0) @ 22 Sa5ae AUS 4)14by9by6mm.......... 61 19 7 6 O60 0 Dj Oo) 4,547 0..-| 13 by'7.5 by 5.5 mma... 60| 34] 21 4 3 4 0] 0| 0|@)| 3,661 am Doz) | 2:bibyi@ byro mime esse SO ilee sol] Maer AiR eae a alia ohare, oie ers ileal Ase foe ae 2,673 AWE 164 | 1225 Dyes Diy proses eee 5 2 15 0 0 SO aks Sees ee eee Qa Doles) Ts byi8i Dye: one se oe 12 11 8 Oke eee eee 5 el ee 3,374 ATES pls: 9) Dyxo ND yp TOME a. sneer 24 1904 a 5) A ee eae ese) Se ete eo | Re eso 3,852 Age: (6.13 by 8 by Gum. .2254- 22 32 5 0 0 0 0 0 | @) 3,113 Aug. 8 | 13:5iby,8:-5 by6.mm-._. 3222 41 19 9 3 OFS @)iiace see Pease A isco eer 4,401 Doz) 12:5iby78 Dyjo-omMie = oe 60 33 8 19 5 0 0] 0|50 2,923 Na fol 2 (ch | a es ARO 2 a Sy Al Paetied U g eA 2 [Perey | Pe oral re eee ml = Mae ee 3,424 1 Died. 4 Apparently injured; died on 25th day.
2 Died on 27th day. 3 Not completely deposited; appears injured.
5 Died on 23d day.
The shortest period which we have observed to be required for incubation was 19 days and the longest was 202 days. During the former period the mean temperature was 87° F., the maximum being 102.5° F. and the minimum 71°F. During the latter period the — mean temperature was 54.26° F., while the maximum was 92.5° F. — and the minimum 14° F. In the laboratory in August eggs hatched as soon as the twentieth day after deposition, an effective tempera- — ture of 820° F. being required for their incubation.
TaBLE XXXVIII.—Incubation of Margaropus annulatus in the laboratory.
SSS
Temperature during incubation. ay . Minimum ¥ Eggs deposited. pee incubation Average |Totaleffec- period. |\aximum.|Minimum.| daily tivetem- mean. perature. , 1908. 1908. Days. mae SURE Odie ORs Mayes te. mer ene ee June 19 29 91.5 68. 79.76 1,065 WUINe QO ena cee eet eee eee July 18 24 94 70.5 82 897 Tialivel 5-22, Fa eRe ee See Eee Aug. 6 22 95 76.5 85.15 969. 50 SANT Oi eres ae eee ee ee ee Aug. 26 20 99 73 85. 51 850. 25 AIG OS SERE Seley rel ee ee Aug. 29 21 96.5 73 84. 76 877 PATS IS i Ce Se er cee eee ne eee Aug. 30 20 96.5 75 84. 88 837.50 oN 0 festa 18 JER ee Oe ex eee Sept. 2 21 96 75 84. 62 74 USS GA = iol eee eet ees Sept. 4 20 96 75 84.01 820. 25
THE NORTH AMERICAN CATTLE TICK. 115
TaBLE XXXIX.—Preoviposition, incubation, and longevity of larve of Margaropus annulatus out of doors.
All larve dead.
Preovi-
poe aie : Minimum Date females | Oviposition osition | atehing | incubation Period | Larval
collected. began. e iat. began. pelind. ay from longevity.
dropping
of female.
}
Days. Days. Days Days
Aug A Aug. 19,1906 13 | Sept. 10, 1906 23 | Apr. 9,1907 211 Mar. 20,1907 | Mar. 24,1907 4 | May 30,1907 68 | July 20,1907 122 51 May 8,1907| May 12,1907 4| June 22,1907 42 | Aug. 27,1907 111 66 July 3,1907| July 6,1907 3 | July 27,1907 23 | Oct. 5,1907 94 69 July 31,1907 | Aug. 3,1907 3 | Aug. 26,1907 24 | Dec. 10,1907 132 106 Aug. 21,1907 | Aug. 25,1907 4 | Sept. 21,1907 28 | May 22,1908 275 244 Sept. 25,1907 | Sept. 30,1907 5 | Mar. 27,1908 180 | June 30,1908 ry 95
Mar. 20,1908 | Mar. 29,1908 9 | May 22,1908 55 | Aug. 13,1908 146 July 1,1908 | July 5,1908 4] July 28,1908 24 | Nov. 8,1908 130 103 July 21,1908 | July 25,1908 4 | Aug. 18,1908 25 | Mar. 31,1909 253 225 Aug. 12,1908 | Aug. 14,1908 2| Sept. 9,1908 27 | May 13,1909 274 246 Sept. 16,1908 | Sept. 23,1908 7 | Dec. 15,1908 84.| May 4,1909 230 140 Oct 5,1908 | Oct. 17,1908 12 | Mar. 23,1909 15 July 5,1909 273 104
May 24,1909 | May 29,1909 5 | June 28,1909 31 | Aug. 15,1909 83 Aug. 2,1909 | Aug. 5,1909 3 | Aug. 27,1909 23 | Sept. 25,1909 54 29 Sept. 6,1909 | Sept. 10,1909 4; Oct. 14,1909 35 | May 7,1910 243 205 Sept. 27,1909 | Oct. 5 7 | Mar. 4,1910 152 | June 12,1910 258 100 Nov. 8,1 Nov. 20, 1909 12 | May 24,1910 186 | July 21,1910 255 58
The larva (Tables XXXIX, XL).—Larve have been found to live as long as 246 days during cool weather and during midsummer from a few days to 100 days. The longevity of the larve given in Table XX XIX is based upon the entire number of eggs deposited by a female, the period being figured from the day the hatching of the lot began until all larve in the lot were dead. All were kept in large tubes with cloth tops and soil bottoms. These were set in the ground beneath a thin burlap shelter; otherwise the conditions were normal.
Molting begins from the fifth to the twelfth day after application to a host and usually all larve molt to nymphs within 16 days after attachment.
The nymph (Table XL).—After the larval skin splits the nymph crawls out and reattaches close to the old point of attachment. The larval skin sometimes remains attached to the host for several days. Nymphs have been found to become engorged and molt to adults as soon as 5 days after the larval molt. The period from attach- ment to the bezinning of molting varies from 13 to 18 days. The length of the molting period of nymphs which become males is fre- quently from 1 to 3 days shorter than for those which become females.
The adult (Table XL).—The number of males and females which transform from a given lot of nymphs is approximately the same. As has been stated, the males usualiy appear from 1 to 3 days before the females. Both sexes crawl from the nymphal skin after it has been ruptured and reattach in the immediate vicinity of the old skin, which frequently remains attached to the host for several days. Before starting in search of mates the males usually feed
116 LIFE HISTORY OF NORTH AMERICAN TICKS.
for a short time, during which the chitin hardens; they then find females, with which they mate, or they may attach beneath engorged nymphs and await their transformation.
Females have been found to engorge and begin dropping on the fourth day after molting. The longest period observed between the first nymphal molt and the dropping of the first female was 14 days. In a large number of infestations the minimum parasitic period (from the application of larve to the beginning of dropping of females) was 20 days. The maximum parasitic period was 59 days and the average was 32 days.
TaBLE XL.—Parasitic period of Margaropus annulatus on bovines.
Period, adult | Period, attachment
First molt. Second molt. Adults dropped. stage. to dropping. Larvee Sq Lat q : : ? i pao) Si applied. 38 ag S E g g E é oS) A Bo} 3 548 g | g g 3 o ex o AS = 43 ae = is ie 4S R = aITey = aaa 2 2 $ q * q o fa] oa, 3 OR — las} (oe) os 3S 3 = > a) as A a ey 4 a = = a = < 1907. 1907. |Days.| 1907. |Days.| 1907. 1907. Days. | Days. | Days. | Days.| Days. Feb. 16 | Feb. 23 7 | Mar. 3 8 | Mar. 12 | Mar. 22 72 9 19 34 24 | 29 July 12} July 18 6 | July 27 9} Aug. 1/| Aug. 9 89 5 13 28 20} 24 1910. 1910. 1910. 1910. 1910. Oct. 14 | Oct. 20 6 | Oct. 29 9| Nov. 5] Nov. 21) 712 7 23 38 22} 30 1911. 1911. 1911. 1911. Dec. 27 | Jan. 8 12 | Jan. 14 6 | Jan. 23 | Feb. 8] 760 9 25 43 PAG | 3s 1911. | Mar. 15 | Mar. 23 See yore eal | 9 | Apr. 10 | Apr. 23 | 212 9 22 39 26 | 32.5 LIFE CYCLE,
At Dallas, Tex., the larve hatching from the entire mass of eggs deposited by a female have been found to survive for a period of 246 — days from the time hatching began. The larvee begin molting from the ~
fifth to the twelfth day after application toa host. 'Thenymphs become engorged and begin molting from the thirteenth to the eighteenth day. Adults sometimes engorge and drop as soon as the fourth day after
the nymphal molt. The minimum period from the attachment of the ~
larve to the dropping of the first engorged female was 20 days and the maximum period was 59 days. Oviposition may commence on
the day following dropping, but usually the preoviposition period is —
at least 3 days. In the summer, when the mean temperature was 87° F., hatching began on the nineteenth day after the beginning of deposition. An effective temperature of at least 820° F. is required
for incubation. The period from the dropping of the engorged —
females to the death of the last larve, or the nonparasitic period, varies from 28 days in summer to 279 days in fall, winter, and spring. In the southern part of the United States all stages of this tick may be found on hosts at any time during the year.
ee ——
THE AUSTRALIAN CATTLE TICK. 117 ECONOMIC IMPORTANCE, NATURAL CONTROL, AND ARTIFICIAL CONTROL.
These subjects are treated in detail in Bulletin 72 of the Bureau of Entomology and in Farmers’ Bulletin 378 of the United States Department of Agriculture.
THE AUSTRALIAN CATTLE TICK. Margaropus annulatus australis (Fuller).
The common name, Australian cattle tick, is taken from the scien- tific name, the latter having been given because the type material was collected in Australia.
DESCRIPTIVE.
Adult.—Males 2.5 by 1.25mm. Females, unengorged, about 2.5 by 1.25 mm.; engorged, 10 by 7.5 by 5 mm. to 12 by 8.5 by 6 mm. The coloration is very similar to that of annulatus proper.
Nymph.—Unengorged, about 1.25 by 0.75 mm.; engorged, about 3 by 2.75 mm. Color very similar to M/. annulatus. Capitulum 0.35 mm. long (from tip of hypostome to base of emargination of scutum); scutum 0.48 mm. long by 0.436 mm. wide.
Larva.—Unengorged, about 0.46 by 0.36 mm.; engorged, about 1.4 by 0.9mm. Color as in Vl. annulatus proper. Capitulum 0.152 mm. long (from tip of palpi to base of emargination of scutum); scutum 0.275 mm. long by 0.356 mm. wide.
Egg.—Ellipsoidal, dark brown, shining, smooth. The average size of 10 eggs measured was 0.531 by 0.406 mm.
HOST RELATIONSHIP.
The host relations of this variety are about the same as those of annulatus proper. Cattle are the principal hosts, but the horse, goat, sheep, dog, rabbit (Lepus euniculus domesticus), and man (for the larve) are reported as hosts by Rohr (1909), who has studied this variety in Brazil. Lahille (1905) reports that in Argentina he has found this tick on horses as well as cattle and has taken it once from the hide of a marsh deer, Blastocerus dichotomus Iliger (B. palu- dosus Desmarest). Newstead (1909), who has studied the ticks of Jamaica, states that in several instances mature specimens of both sexes were found on the dog. He reports it to be a general belief in Jamaica that the larva of this variety will attack any vertebrate ani- mal that comes its way, but fails to present instances. He fur- ther states that the larva is a great pest to man. The habit of the larva of attaching to man as reported by Newstead and by Rohr appears to be similar to that of Margaropus annulatus decoloratus and unlike M. annulatus proper, which as a larva never attaches to a
118 LIFE HISTORY OF NORTH AMERICAN TICKS.
human host. The hosts reported by Neumann are cattle, horse, sheep, dog, and deer. One of the authors (Bishopp) found this tick in great numbers on cattle at Tampico, Mex., but very few were taken on horses. Mr. G. N. Wolcott has collected it on both horses and cattle in the Province of Pinar del Rio, Cuba.
GEOGRAPHICAL DISTRIBUTION.
This variety, which Neumann considers as including microplus, has a wide distribution. It undoubtedly occurs in all of the countries of South America, having been reported from British Guiana, Brazil, Paraguay, Uruguay, Argentina, and Chile. It is known to occur as far north as Tampico, Mex., where it was found to be a bad pest. In Central America it has been reported from Guatemala, Costa Rica, and Panama. It appears to be widely distributed in the West Indies, having been reported from Cuba, Jamaica, Porto Rico, Antigua, Guadeloupe, Dominica, and Trinidad.
The variety was described from Australia, where it has quite a wide distribution. It has also been reported from the Malay Archi- pelago (from Borneo and Sumatra), and Lounsbury has found it, as well as another variety, decoloratus, to occur in Cape Colony. C. S. Banks (1904) has reported the finding of this tick upon cattle which had arrived in the Philippine Islands 26 days before. He suggests that the ticks may have attached after arriving at Manila, in which case it may occur throughout those islands. From what he says in regard to the occurrence of larve on and in buildings near Manila where cattle are kept, it seems quite probable that this tick occurs there.
LIFE HISTORY.
Observations on the biology of this variety have been made by Pound (1899) in Australia, Lounsbury (1905) in Cape Colony, Ligniéres (1900), and Lahille (1904) in Argentina, Rohr (1909) in Brazil, and Newstead (1909) in Jamaica.
The egg (Table XLI).—In one instance oviposition commenced on the day following dropping and in another on the second day. Fe- males which dropped on April 30, 1908, and were placed out of doors in tubes on sand commenced oviposition in from 5 to 13 days. The period of deposition as observed in 5 ticks varied from 15 to 23 days. The largest number of eggs deposited by any one of 11 ticks observed was 4,459 in which instance oviposition commenced on September 4, the second day following dropping. This female, which measured 12 by 8 by 5.5 mm., was the second largest tick observed. The average number of eggs deposited, based upon the 11 ticks observed, was 3,424. Rohr reports 3,046 to have been the maximum number of eggs deposited by any tick observed by him, with 1,529 as the minimum and 2,471 as the average for some 18 ticks. .
THE AUSTRALIAN CATTLE TICK. 119
Taste XLI.—Incubation and larval longevity of Margaropus annulatus australis.
IN THE LABORATORY.
| |
Temperature during incubation.
E Minimum < ag omar incuba- aston lag ; Larval ited. gan. tion ead. ongevity.| F ei 5 Average | Total pos | period. | a Minimum. daily mean| effective. |
5 | 10% | Dave | Days. | Fr °F. Fa =
yl ee cd ess See 2 ee eee -o 3 77.76 5 May 14/| June 6 De a Be os Se Eh 88.5 65.0 78.14 843.50 May 16/ June 8 yee paste” 90.0 68.0 79. 09 866. 25
OUT OF DOORS.
May 5| June 6 33 | August 7 82 91.0 43.0 75.31 1,066.1 May 6/j June 8 34 | August 15 68 93.0 43.0 76. 04 1,123.2 May 7| June 9 34 | August 19 71 93.0 43.0 76. 69 1,145.5 May 8j| June 8 32 | August 14 67 93.0 43.0 77.16 1,093.0 May 11 | June 10 31 | August 7 58 93.0 60.5 77.93 1,082.8 May 13| June 8 27 | August 24 77 93.0 60.5 77.87 941.6
Three lots of eggs, deposited May 13, 14, and 16, respectively, which were kept in the laboratory at a mean temperature of 77.8° F., hatched in 24 days, a total effective temperature of 834° F. being re- quired for their incubation. Eggs which were deposited by ticks in tubes out of doors from May 5 to May 13 commenced to hatch in from 27 to 34 days. Rohr states that at a mean temperature of 30° C. (86° F.) eggs hatched in 19 to 23 days and at 35°C. (95° F.) in from 15 to 18 days. In this case the total effective temperature would be lowered somewhat. Lahille reports an instance in which eggs hatched in 20 days but does not give temperature records. He states that in one instance eggs deposited on April 30 passed the cold months and hatched September 6, or 129 days later.
The larva (Tables XLI-XLIV).—Our observations on the lon- gevity of the larve are based upon the progeny of 6 ticks which dropped from a host on April 30, 1908, and which were at once placed in tubes on sand out of doors. The eggs from these ticks, which commenced depositing from May 5 to 13, were left with the ticks and commenced to hatch from June 6 to 10. The larve in the several tubes were all found to have died between August 7 and 24, or a Maximum period of 82 days from the date the larve commenced to hatch. Thus it appears that at Dallas the progeny of ticks which dropped April 30 were all dead on August 24, or in a period of 116 days after the females dropped.
The larval molt occurs as soon as the sixth day after attachment, the last observed to molt having done so on the ninth day. Pound states that the molt takes place on the seventh day, Lahille reports it to occur from the seventh to the ninth day, while Rohr found 7 or 8 days to be required.
120 LIFE HISTORY OF NORTH AMERICAN TICKS.
TaBLeE XLII.—WNonparasitic period of Margaropus annulatus australis.
All larvee dead. Female raat Preovipo- Li oe Oviposi- ys Hatching | ; F Larval dropped : sition incubation Peri neat engorged. tion began. period. began. period. ie a oe et longevity. female. 1908 1908 Days 1908 Days 1908 Days Days iN ig) BWsnecose May 5 5 | Jume'G---.- Aug. 27 ] U7 005 3\) eee May 6....- 6 | June 8..... 33 | Aug. 15 107 68 Aprs30). m5 May 7 7 )) dune9-- eee 33 | Aug. 19 111 71 Aprrs0nc cat 2 May 8. 8 | June 8....- 31 | Aug. 14 106 67 JNO B eso kaqee May 11 11 | June 10 30" | ANTE cee 99 ANODE US6a50Rr May 13 13 || June $2.--- 25 | Aug. 24 116 77
The nymph (Tables XLIII-XLIV).—The nymphs were found to molt as soon as the eighth day, or 14 days after attachment, the last observed molting on the thirteenth day, or 19 days after attach- ment. It was observed that in molting, as in annulatus proper, the young nymphs detach from the old point of attachment and reattach about one-eighth of an inch away, the old skins remaining attached to the hide after being shed.
Pound reports 7 days to be required for the nymphal stage, while Lahille places this period at 9 days.
The adult (Tables XLIII-XLIV).—In molting the females, like the nymphs, move from the old points of attachment, leaving the skins, and attach from one-sixteenth to one-eighth of an inch away. The mating habits of australis are similar to those of annulatus proper. After molting the male feeds for a number of hours and then starts in search of a mate with which, when found, it may remain until the female drops engorged. Males have been observed to remain in the position of copulation with females of Margaropus annulatus and Dermacentor nitens as long as 3 days. Lahille has observed copulation to take place off the host. We have not deter- mined the period that the males remain upon the host, but Lounsbury states that it is usually about a month.
The adults have engorged and dropped as soon as the twenty- second day after attachment or 8 days after molting. In three infestations observed, the last engorged female dropped on the twenty-seventh day from attachment, or 9 days after the last nymph was observed to molt. Lounsbury reports the parasitic period (from the application of larve to the dropping of the females) to be from 18 to 38 days, but usually 23 days.
THE AUSTRALIAN CATTLE TICK. 121
TaBLE XLIII.—The parasitic period of Margaropus annulatus australis. INFESTATION No. 1.
Date. Remarks. 1908. : Leh oh ne eo oe Larve placed on bovine. Apr. é SE CC § Spee ee All attached. me 12: (Gt GS) s-.- 92 6. 52225 Several larve molting. Ud (2 Op ee re A large percentage molted. impr. 14.(S8th day). 222:-------5- All larve molted. pr, 2 (ibihn day).-.-.-.------- Four nymphs molted (3 males, 1 female). Apriae (16th day). .<----.2.2-- A total of 20 molted. mpEees (Lith OS)... ~-=3-5- A total of 40 molted; one not molted. impr 24 (18th day). 2.-2--.-2s- All have molted Apr. 25 (19th day)..-......----- Several mated. / Apr. 27 (21st day).......----..-]| One female fully engorged but still attached. Apr. 28 (22d day).......---.-.-| One female dropped engorged. al 2 5" Ob ee Two females dropped. Seven fully engorged still attached. PaO 24. ARV) =~. 222-2 22% Fourteen females dropped engorged. AL eo 8 ae Four females dropped engorged. MA OO GRY) 2 oc2. 605225 The last female dropped engorged.
INFESTATION No. 2.
2 STAR Gyn ley ES ee Larve (hatched July 11) placed on bovine. Ame 2 CIsbOay). .\. 2-2-2525. - All attached.
aie {LEG ORY) 25... ~22ces = Several molting.
aS GRY)...---30L2-<2- All but two or three have molted.
mae AS(Sth Ay)... 2s. = All have molted.
Aap. 25 (14th day)-_..--<---..-- Two nymphs molted to males.
Aug. 26 (15th day)...........-. Three more have molted.
Auge 2S (ith Gay)_..--.--=-.-- All have molted.
Aug. 29 (18th day)........-.-...- All mated.
Sept. 1 oe pel & Ave eee Several females fully engorged
a 7 Dg er Six females dropped engorged.
Aug. 4 (24th a DS: SAS yet Five females, the last, dropped engorged.
INFESTATION No. 3.
ty SS ees Larve (hatched July 11) placed on bovine. Aug. 21 1(1 & wins pees ia ees All attached.
sie? P56 AGUA GAY). ----=-- ------ Several molted.
Asie: 20 (9th Gay)..---.--.--=-- All have molted.
Sept. 5 (16th day).......-..---.-| Several nymphs molting.
Sept. 8 (19th day).............-| All the nymphs have molted.
Sept. 12 (23d day).............-.| Four females fully engorged.
Sept. 13 (24th day)...........--| Four females dropped engorged and several others are fully engorged. Sept. 14 (25th day).............| Eighteen fully engorged females were removed. Sept. 17 (28th day).............| One fully engorged female removed.
Sept. 18 (29th day).............| One fully engorged female, the last, removed.
TaBLE XLIV.—Summary of parasitic periods of Margaropus annulatus australis.
Larve. Nymphs. In- First molted. Last molted. First molted. Last molted.
3 2 es MS Vicia Pts tion. Period Period ollow- on- }Attached. Ps follow- a follow- Ms 7 Para- ge
ate. | ing at- ate. | ing at- ate. come e- ate. | sitic 2 tach- tach- al riod. | ment ment. ment
1908. 1908 Days. 1908 Days. 1908 Days. | 1908. Days. | Days aoe Apr. 6] Apr. 12 6 | Apr. 14 8 | Apr. 21 9 | Apr. 24 12 15-18 , See Aug. 11} Aug. 17 6 | Aug. 19 8 | Aug. 25 8 | Aug. 28 11 14-17 - Sean Aug. 20} Aug. 26 6 | Aug. 29 9 | Sept. 5 Sept. 8 13 16-19
193 LIFE HISTORY OF NORTH AMERICAN TICKS.
TaBLe XLIV.—Summary of parasitic periods of Margaropus annulatus australis—
Continued. Females dropped. Infestation. First. — Period SS OM OTE, Wate Parasitic Hake Parasitic pales tn
period. period.
ee —_— |} $$$ —$
LIFE CYCLE.
Under favorable conditions the progeny of a single tick may survive for a period of 82 days from the date hatching commences. The larvee usually molt on the sixth day following attachment to the host, although in some instances as many as 9 days may be required. The nymphs usually molt in from 8 to 10 days later, but as many as 13 days have been observed to be required in some instances. Adults have been found to engorge in 7 days. In our observations the last females dropped engorged on the twenty-ninth day from attachment, but the period would probably be longer if males were not present. In one instance oviposition commenced on the day following dropping, but usually several days pass before such takes place. In June, at a mean temperature of 78° F., hatching began on the twenty-third day. An effective temperature of 834° F. appears to be required for incubation.
ECONOMIC IMPORTANCE.
This tick is so closely related to our species (Margaropus annulatus) that what has been said of annulatus proper regarding its impor- tance as a pest may also apply to it. Im the countries where it occurs australis is the same great pest that annulatus is in the southern United States, and transmits Piroplasma bigeminum in a similar manner. The habit of the larve in attaching to man, how- ever, adds to its importance.
NATURAL CONTROL.
Ds ee ee ee, ee
THE GOPHER-TORTOISE TICK. 123 ARTIFICIAL CONTROL.
The methods applicable in the control of annulatus proper apply in a general way to australis. Our observations indicate that the longevity of the larve may be somewhat shorter than that of annu- latus. The long periods of warm weather in the Tropics should greatly assist in its eradication through starvation. If, however, the larve attach to small animals, as has been reported by Newstead (1909), and these develop to adults in any numbers, its eradication will be much more difficult.
Genus AMBLYOMMA Koch.
The five species of the genus Amblyomma which occur in the United States, namely, americanum, cajennense, dissimile, maculatum, and tuberculatum, have been studied and are considered in the following pages. The other species of this genus whose biology has been studied are variegatum by Barber (1894-95), in Antigua, goldii and varium by Rohr (1909), in Brazil, and hebreum (1899), marmoreum, and variegatum (1905), by Lounsbury, in South Africa. All five species which occur in this country and the three species studied in South Africa dropto pass thetwomolts. This also appears to be the case with the Brazilian species studied. Aside from the species which as adults attach to cold-blooded hosts only (dissimile, goldii, marmoreum, tuberculatum), the host relationship is not closely restricted. The species are able to withstand long periods of fasting while waiting fora host. While americanum is widely distributed, occurring in the Boreal and Austral regions, the other four species have only been found in the Tropical and Lower Austral Zones, three of these occurring only in the Gulf strip of the Austral Zone. The species are very hardy, yet require some protection, such as timber or underbrush; maculatum, however, exists on the prairie.
Only one species is known to transmit disease, namely, hebreum, which conveys the infection of heartwater of sheep, goats, and cattle in South Africa. Experiments to determine the possibility of americanum acting as a transmitter of splenetic fever of cattle have been conducted by two investigators. In both cases the results were negative.
THE GOPHER-TORTOISE TICK.
Amblyomma tuberculatum Marx.
The common name of the species is taken from the host of the adult.
DESCRIPTIVE. Adult (Pl. IX, figs. 4-8).—Males from 7 by 4.5 mm. to 8 by 5 mm. Females, unengorged, 7 by 5 mm. to 10 by 6 mm.; engorged, 19 by 13.5 by 8 mm. to 24 by 18.5 by 11 mm. Males, scutum reddish
124 LIFE HISTORY OF NORTH AMERICAN TICKS.
brown, with a somewhat complicated pattern, formed by rather broad metallic bands. Female reddish brown, scutum with a large silvery mark on each side, containing one or two dark spots, and two divaricate, silvery stripes extending forward from the hind margin and sometimes connected with the lateral spots.
Nymph (Pl. IX, figs. 2, 3)—Unengorged, 2.25 by 1.5 mm. to 4 by 2.5mm.; engorged, 7 by 5 by 2.5 mm. to 10 by 6.5 by 4 mm.; capit- ulum 0.932 mm. long (from tip of palpi to base of emargination of scutum); scutum 1.2 mm. long by 1.6 mm. wide. Unengorged nymphs are reddish brown; the scutum has a large silvery spot on each side, united behind at the tips and in front much broken by the large punctures. Engorged nymphs are dark gray in color.
Larva (Pl. IX, fig. 1)—Unengorged, about 1.03 by 0.76 mm.; engorged, about 4 by 3 by 1.5mm. The color unengorged is brown- ish yellow, intestines showing through darker; lateral margins of the scutum of a pinkish color. The color of the engorged larve varies considerably; partially engorged specimens are usually dull gray and those which are fully engorged or nearly so usually have a purple color. Larve that have been fully engorged for some time have a bluish brown color.
FEgg.—Ellipsoidal, reddish brown, shining, smooth. Maximum for 10 eggs measured 0.893 by 0.647 mm.; minimum 0.847 by 0.647 mm.; average 0.864 by 0.655 mm.
HOST RELATIONSHIP.
The adults of this tick have been collected from the gopher tortoise only. Experimental attempts to attach them to bovines have failed. The nymphs are commonly found on the gopher tortoise and have been engorged in experiments upon a bovine. Engorged larvee have been collected in large numbers from dogs and rabbits and in smaller numbers from cattle and two birds of prey, namely, the owl and the hawk. The fact that the bird hosts discovered have been birds of prey has suggested the thought that the larve crawled to the bird host from the small mammals devoured by them.
GEOGPAPHICAL DISTRIBUTION.
(Fig. 8.)
Bul. 106, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE IX.
Fig. 1—Unengorged larva. Fig. 2—Unengorged nymph. Fig. 3.—Engorged nymph. Fig. 4.— Engorged female, dorsal view. Fig. 5.—Females engorging on tortoise’s feet. Fig. 6.—Male, dorsal view. Fig. 7—Unengorged female, dorsal view. Fig. 8.—Engorged female, ventral view. (Orig- inal.)
r (65 Hu Pai denieh am ny bis x me im r! - f ¥ F o¢ Comp Loa foebae . vat sa i OATS Biers 1 4 * 4 "s : wae . ~ - ‘ . 2 ‘ . + ae ae P gai cat NEDAr
THE GOPHER-TORTOISE TICK. 125
LIFE HISTORY.
Observations on the biology of this tick have been published by Hooker (1909a).
The egg (Table XLV).— Three females were engorged upon a box tortoise. Their respective dimensions were: 24 by 18.5 by 11
Fic. 8.—The gopher-tortoise tick, Amblyomma tuberculatum: Distribution. The large dots show localities where the species has been collected in our investigation. The small dots indicate the probable range of the tick. (Original.)
mm.; 19 by 13.5 by 10 mm. and 19 by 13.5 by 8 mm. The first female weighed 2.35 grams. This and the last female had a pre-
oviposition period of 8 days at a mean temperature of 84° F. The second female began depositing on the tenth day after dropping.
126 LIFE HISTORY OF NORTH AMERICAN TICKS.
The deposition period of the first and second females was 21 and 16 days respectively. The largest number of eggs deposited was 5,481; the average 3,839. Oviposition continued in one case for 21 days.
Many of the eggs deposited by these females were black and shriy- eled when deposited and ultimately only a very small percentage of them hatched. It is believed that in nature several thousand more eggs would be deposited, as the females observed by us were still of large size when deposition ceased. The first female recorded in the table died on the thirty-fourth day after dropping and the second female died on the twenty-eighth day. Although the engorged — females are much larger than in Amblyomma maculatum, the number of eggs deposited is probably less, due to the much larger size of the eges of tuberculatum. The process of oviposition is very similar to that of the South African species of Amblyomma as described and illustrated by Lewis (1892). The viscid membranes or papille are protruded from between the capitulum and the scutum to a far greater extent than in Margaropus annulatus, as observed by Cush- man (see p. 73). This membrane is prolonged into two horns, or arms (see fig. 9), by means of which the fluid is directed to the eggs as deposited. At the writers’ request, Mr. R. A. Cushman has made the accompanying drawing of this organ.
The incubation period appears to be longer than in the other species of Amblyomma observed, 91 days being the minimum period recorded. The average mean temperature during this period was 70.19° F. and the total effective temperature 2,474° F. Under natural conditions this period may be somewhat shorter. The records given in the accompanying table were all made upon eggs kept in the laboratory on moist sand. Only a very small percentage of those deposited hatched, many of them being shriveled and black when deposited.
TABLE XLV.—/Jncubation and larval longevity of Amblyomma tuberculatum.
r s Salts ‘oul Mini- emperature during incubation
Eggs. + mum Larval depos Habeas incuba- All larvee dead. longev- ‘Acverace | eee ited. ean tion ity. Maxi- Mini- ake fees period. mum. mum. anaes, ial 90 190 Days Days std oF seh of Aug. 27 .| Dec. 4..... Dech22) (9085s -2--- 18 97.5 34.0 70. 26 2,726 Aug. 29 .| Nov. 27 91 Mar, 2-17, 1909....-.-} 95-110 97.5 34.0 70.19 2,474 PATI cl ss) MDC Cr aces 96 Dees22 1908- = 3.2 — 18 97.5 34.0 69. 63 . 2,008 Sept.1 Dec: 4.552% 95 Mar. 3-20, 1909-- 94-105 97.5 34.0 69. 47 2,515 Sept. 7 Dec. 4-29... 114— | Jan. 13, 1909......-- Dar a|saceeece te | obese aoe od) aoe ee
The larva (Table XLV).—The greatest larval longevity observed by us was between 95 and 110 days. None of the lots, the longevity of which is recorded in Table XLV, contained more than 200 speci- mens and the three lots which had a longevity of from 15 to 18 days
THE GOPHER-TORTOISE TICK. 127
each contained only one or two larve. Three slightly engorged larve collected from a rabbit on December 21, 1907, were placed upon a bovine on March 10; two were found attached the following day, while the third was found dead on March 12. While the two ticks remained attached for only a few days, the fact that they reattached shows the possession of considerable vitality. A few specimens of a lot of larve from one-fourth to three-fourths engorged when col- lected November 30, 1908, lived for three months.
Engorged larve taken from a rabbit on December 21, 1907, and kept in the laboratory at a mean temperature of 61.4° F., did not com- mence to molt until 86 days later, having required a total effective temperature of 1,583° F. Engorged larvee collected in November began to molt in from 107 to 147 days.
On the dog no particular preference as to position of attachment was observed, but on the rabbit the larve were found in great patches near the base of the ears, a few being in and on the ears. Larve have been taken in abundance on dogs and rabbits and a few speci- mens on cattle and sparrowhawks.
The nymph (Tables XLVI, XLVII).—On June 8, 1909, one nymph was alive in a tube which contained 8 specimens that molted from larvee between March 15 and March 30, 1909. This individual had.lived between 70 and 80 days up to the time it was put on a host ae = Fee ee ek rag etre pha Setthchi vetaed tet rose tna eouttin whit eapttabin molted March 11, 1909, was alive in position to receive an egg from the oviposi- and able to attach to a host when " S™*UY onlateed. Original.) applied on May 31, 1909, a period of 81 days after molting. Other lots which molted in March, 1909, and were kept on sand died in from 27 to 56 days. It should be stated that all of these nymphs were collected as larve late in the fall of 1908 and did not molt until March. Probably specimens -dropping during warm weather so that they would molt to nymphs in a short time would live for a much longer period.
Nymphs were found to attach readily to a bovine, but some trouble was experienced on account of scabs forming around the mouth- parts and causing the ticks to drop before becoming fully engorged. Specimens were found to change their point of attachment several times before imbibing much blood. The shortest period in which engorgement took place upon a bovine was 8 days, the greater number dropping on the ninth and tenth days, the last to leave the
128 LIFE HISTORY OF NORTH AMERICAN TICKS.
host dropping on the eleventh day. Upon a cold-blooded host the period of engorgement will undoubtedly be found to be much longer, as was found to be the case with Ambylomma dissimile. Attempts to get nymphs to attach to a horned toad were unsuccessful.
TABLE XLVI.—Engorgement of nymphs of Amblyomma tuberculatum.
Nymphs dropped engorged—days following
application. Total Date nymphs applied. Host. ee
Pho | Bo) a [ep Tegel eal) oat ge | ton ater abet PARTS 1411908 2 ober eee bi cleeieiereree Bowine ==.) 0) Ov OnlenOsly (Ons Ob S0n|e OntaOblbeou lead a ee 15, MONS Fo mercies cee an cteeoa| sees doeie.: OA OS) BOE MO Wap Oeliee@eai ie ah tei) Spe & 8 BV 20 5 AOOR NS a atrae lene siete stores ett yaal| jaar GOsrsee OF OM On Oss Ol) SOM On ela een wee 10 May: (5 1909S 2 Act clase cumiaes oa -ee =| Seer donee... On OR SOR ORO On| Oh ienttn | iO)n On| pO) 1 Mary. lil’, 1909) Ooi so ee oe Were wa eres cee ae GOn acer OF SOR Ose OF SO SOR Onis On esOn ies |e? 3
At a mean temperature of 81° F. nymphs which dropped the last of May commenced to molt in 29 days, a total effective temperature of 1,104° F. having been required. The molting period of nymphs which become males and females is about the same. It was found that when the engorged nymphs were placed in tubes on moist sand they at once burrowed into it out of sight. When examined they were found an inch or more beneath the surface, in which position molting took place. This habit was not observed in engorged larvae, but is probably the same. Although observations on this habit have not been made in other species of ticks, owing largely to the fact that it was necessary to keep them on an impenetrable surface in order that the exact dates of molting could be observed, it seems quite probable that some of them may do so also. Such a habit is of great advantage to the tick in protecting it from enemies during the quiescent period, as well as in preventing drying out.
TasLteE XLVII.—WMolting of engorged nymphs of Amblyomma tuberculatum engorged on bovine.
Temperature from
Engorged nymphs molted—days following drop- | Number dropping to date
ping. molted. | frst tick molted.
Date engorged nymphs \"ber. Aver TO 3 ! a ver- -| || Maxi-| Mini-| age 29) 32] 36] 37) 38] 39] 44) 46] 48] 49) 51] 53] 66/203/207 é 8 "3 | mum. |mum. | daily g 2 = mean.
Apr. 23,1908] 1] of of of of o| of of of of of of lta] of of a] of 3] 91.8) — 47] 76.29 Apr. 24,1908} | of of of of of of of ofofedts|ig] of of of 2 4) 6 89 47| 74.72 Apr. 25,1908/ | o of ol of of of otabeol ono] of of of of a] af al 80 47| 74.73 Apr. 26,1908} 2] o| of o| of of of of o| og] Of of of of of of a] a} 91.8) 47] 75.11 May 28,1908] i] 0! o| oc of of o| of of Of of of of of of a] Of i} 91-5] 69) 80.50 May 29,1908] 4] 0] of19] 1g 19119] Of of of of of O| of of 3] 3| 4} 91.5] 69) 80.61 May 30,1908} 3lig] cl O| of of of o| of of of 0} of of of of 3) Of a] 91-5] 69) 81.08 May 31,1908} 2] 0 oct} o| of of o| of of o| of of of of 3 a] 2} 91-5 69) 81
Nov.24;1908| i] 0] of of 0| of of of ol of of of | 0| 019] of 3 i} 100 17| 67.15 Dec. 2,1908| 1 o| of o| of of of of o| of cl o| of og] of 3] Of 3} 100 17| 67.89 May 21,1909] —1{19] of 0} of of of of o| of of 0 of of of of of | 4} 100 47| 86.17 May 22,1909] 1 0| 1] | of o| O| of o| of of of of of Of O..¥...- ee 47| 86.56
Total .. 7:1 meee | ame (ae | Mv | ei Has Pa Ps) Flee) NE |S le Te call CM OTA zs
THE GOPHER-TORTOISE TICK. 129
The adult—Among the individuals observed to molt to the adult stage there was a predominance of females. The greatest adult longevity observed was about 90 days; other specimens lived from 17 to 76 days. All of these records were made during midsummer. A few ticks of both sexes remained active, when kept in tubes in the laboratory, for more than 2 months during the summer before being placed upon a host. It is certain that with abundant material, placed under natural conditions, adults would be found to live much longer than those observed by us.
Several males and 3 females placed upon a tortoise on July 29, 1908, readily attached. The first female to engorge dropped 20 days later, measuring 24 by 18.5 by 11 mm. Next to Amblyomma varium, which has been recorded by Rohr (1909, p. 120) as measuring 28 by 24 by 15 mm., this is the largest tick on record. The second female dropped engorged on the twenty-first day after attachment and measured 19 by 13.5 by 10 mm. The third female dropped on the _ twenty-fifth day after attachment and measured 19 by 13.5 by 8 mm. During the period of attachment none of these females was observed in copulation. Upon removing the first female from the bag in which the tortoise had been placed it was found apparently in copulation with a male which had also dropped from the host. This fact suggests the possibility that copulation takes place after the female drops engorged.
Males have been observed to remain attached for a long time after the females drop, and this habit accounts for their being more com- monly met with upon tortoises. One of the three males which at- tached to a tortoise July 29, 1908, remained on the host 43 days after the last female dropped and the other was still attached but dead when the tortoise died on January 5, 1909, thus having been attached 135 days after the last female dropped, or a total period of 160 days. The males attached to the margin of the shell as well as to the body of the tortoise. It is conceivable that the females may also thus attach to the shell, but if this actually occurs the period of en- gorgement must be greatly prolonged owing to the poor blood supply. Attempts to secure the attachment of adults to horned toads (Phrynosoma cornutum) were unsuccessful.
LIFE CYCLE.
Larve may live for at least 95 days during the winter months. The period required for engorgement has not been determined. At winter temperature in the laboratory at Dallas 86 days passed before molting commenced. During this period a total effective temperature of 1,583° F. was accumulated. The longest molting period recorded was 165 days. The greatest nymphal longevity
21448°—Bull. 106—12——-9 ;
130 LIFE HISTORY OF NORTH AMERICAN TICKS.
recorded was 81 days. At the end of this period one specimen was still able to attach to the host. On a warm-blooded host the nymphs may engorge in 8 days and molting may commence as soon as 29 days after dropping. A total effective temperature of 1,104° F. appears to be required to produce this molt. Adults may live for 90 days and engorge as soon as 20 days after application to a host. Oviposition may commence as soon as the eighth day after dropping and as many as 5,481 eggs may be deposited. The minimum incu- bation period recorded (in winter) was 92 days. During this period a total effective temperature of 2,474° F. was accumulated.
ECONOMIC IMPORTANCE.
While this tick has not been considered of economic importance, the fact that it occurs on cattle and in large numbers on dogs and - certain small mammals suggests the possibility of its becoming so.
NATURAL CONTROL.
No particular enemies of this tick have been observed. However, in experiments several ticks were lost by being devoured by the
tortoise. THE IGUANA TICK.
Amblyomma dissimile Koch.
The common name of this species is given it because the iguana was the first animal upon which we collected it as well as being one of its most common hosts. Newstead (1909, p. 445) has made use of the name “bullfrog tick.”
DESCRIPTIVE.
Adult (Pl. X, figs. 3-5)—Males from 4 by 2.75 mm. to 5.25 by 3.33 mm. Females, unengorged, from 4 by 2.5 mm. to 5.5 by 3.75 mim.; engorged, from 14 by 9 by 5 mm. to 17 by 10 by6 mm. New- stead has described the coloration of the engorged female as ochreous to yellowish gray; scutum chocolate brown with dull coppery mark- ings, forming a distinct spot at the apex.
Nymph (Pl. X, fig. 2).—Unengorged, about 2 by 1.1 mm.; color varying from light to a darker brown. Length of capitulum 0.497 mm. (from tip of palpi to base of emargination of scutum); scutum 0.737 mm. long by 0.983 mm. wide. Engorged, from 4.5 by 3 by 2 mm. to 5 by 3.25 by 2mm. The color varies according to whether blood or lymph has been engorged, the lymph giving a light gray, and the blood a brownish yellow color.
Larva (Pl. X, fig. 1)—Unengorged, from 0.867 by 0.578 mm. to 0.961 by 0.617 mm.; engorged, 2 by 1.15mm. Capitulum 0.236 mm. long (from tip of palpi to base of emargination of scutum); scutum
THE IGUANA TICK. 131
0.9 mm. long by 0.6 mm. wide. The color varies as does that of the nymphs, a somewhat higher percentage of this species than others having a light gray color. A few have a pink color when they drop.
Egg.—Ellipsoidal, light brown, shining, smooth. The maximum size for 10 was 0.677 by 0.570 mm., the minimum 0.631 by 0.539 mm., with an average of 0.652 by 0.560 mm.
HOST RELATIONSHIP.
The type host is not known. This tick attaches to cold-blooded animals, particularly iguanas and toads, upon both of which it engorged at Dallas. The toad, however, died before the larve all engorged, due to being confined in a cage. In rearing experiments the larve and nymphs readily attached to and engorged upon a bovine, but the adults would attach to cold-blooded hosts only. It thus seems probable that in nature the immature stages attach to both cold and warm blooded animals and that the adults attach only to the former class. Newstead states that in Jamaica it is apparently confined to the common toad or so-called ‘ bullfrog” of the island (Bufo marinus).
GEOGRAPHICAL DISTRIBUTION.
The type locality is Mexico. During 1907 nymphs and adults of this species were collected by one of the authors (Wood) from iguanas which had been brought to Brownsville, Tex., from the Isthmus of Tehuantepec. The species has been recorded from Mexico, Guate- * mala, Honduras, Nicaragua, Panama, Jamaica, Antigua, Barbados, Trinidad, Colombia, Venezuela, Guiana, Brazil, Paraguay, Argentina,
and the Philippine Islands.
LIFE HISTORY.
- The only information upon the biology of this tick that the authors have found is furnished by Newstead (1909). This author is in error in supposing that the molts are passed upon the host, as such is not the case.
Egg (Tables XLVIII, XLIX).—In the laboratory in June and July at a mean temperature of 82° to 86° F. oviposition commenced on the sixth day after dropping and continued for 16 and 17 days. The larger number of eggs deposited by the two females from which counts were made was 1,655. Newstead (1909, p. 446), however, records 1,784 from one female, deposition commencing on the seventh day and continuing for 17 days. The minimum incubation period recorded by us was 27 days. This record was made on eggs deposited early in August. The mean temperature during incubation was 85° F. An effective temperature of 1,133° F. appears to be required for the incubation of the eggs. The first tick, the oviposition of which
132 LIFE HISTORY OF NORTH AMERICAN TICKS.
is recorded in the following table, was about three-fourths engorged, having been collected on aniguana. The second female was engorged on a box turtle and measured 14 by 9 by 5 mm. It died on the twenty-fifth day after dropping.
TABLE XLVIII.—Oviposition of Amblyomma dissimile.
Number of eggs deposited—days following dropping.
Date engorged Total female number dropped. | ¢ | 7 | 8 | 9 | 10 | 11 | 12/13] 14] 15] 16| 17] 18| 19 | 20 | 21 | a2 | Ofeees-
June 2,1908....| 235 | 342 | 208 | 275 | 134 | 158 | 70 | 25 | 21 | 36 | 26 | 16; 10} 5} 0) 10) 2 1,573 July 30,1908.-.-| 186 | 318 | 317 | 283 | 132 | 142 | 95 | 64 | 38 | 32} 18 | 7) 12) 5) 2
Average. :|...-- Secaucus eases Pea ale gs ns ee 1,614
TaBLE XLIX.—/Jncubation and larval longevity of Amblyomma dissimile.
Temperature during incubation. . Minimum Eggs de- Hatching} - : 2 Larval posited. began. PRE ie eI NET VEBULE GL longevity.) yraxi- | Mini. | AYerage | Total P : Fa | aaa daily effect- : * | mean. ive. 1908 Days. 1908 Days. PIO, pels swan Se Mayans soceooe es June 13 . AD | ited Senos tee ee | tees 91.5 56 76.93 | 18075 Maynke nos: June 21 BO oss bey ses were ee cee ecieeemnee 91.5 68 80. 57 | 1,283.5 Tune Oesss. - July 14 BOu | NOGho Wires aes sae 95 93.5 69 81.00 | 1,368 June 13, 14...:- July 15 33 | Before Oct: 7... --- 84 93.5 70. 5 81.46 | 1,269 ANOS Meee all dbl be Oem 34) \OCENZR ies eee 74 90 70. 5 82.01 | 1,326 SAIS HG eee Ee Aug. 31. 27 NOWa 13-26". 4a. SEE 74-87 99 73 85.17 | 1,138.5 ATI OSs a= Sept. 2.. Pe NO Veal g—2Oeeeeeees 72-85 99 7. 84.96 | 1,133. ANE <8, j9F 222% dz Sept. 5..| 29 | Nov. 26-Dec. 9..-- 82-95 96. 5 73 84.53 | 1,204.5 Aug. 11-14..... Sept. 7..| 280 INO Vel G ao ponere 70 98.5 75 84.87 | 1,172
Larva (Tables XLIX—LI) —The longevity of larve which hatched on July 14, 1908, was 95 days. This was the greatest longevity observed by us. Engorgement took place on a bovine as soon as 4 days, the greatest number dropping from the fifth to seventh days. On a cold-blooded host (a tortoise) 10 days were required for en- gorgement. Ticks placed upon a bovine had all dropped on the ninth day, whereas upon a tortoise the last dropped upon the six- teenth day. An important point is here brought out in the fact that upon cold-blooded animals a much longer period is required for en- gorgement.
TaBLe L.—Engorgement of larvx of Amblyomma dissimile.
Larvae dropped engorged—days following applica-
tion. Total Date larve applied. Host. | re
a5) 64718 1 9 110) ff) 42) 14)) 95] 16) ae
1908.
TU Qo es ae Soe see sae aes Bovines=-2) 125) 29a40 23. es esr) On| Oss inn en On| iG) 120 JUV 23 seen see aise oes Saree a TRortoise--5 |) 10) 101) 10) J0F) SON SOr!, (Gt Su I2r AGA Sais 43 USS AS ceiece sce - See eee Boyines- sol e983) 4 es |e Ou} On| sOn 205 Os On On en0 16
Bul. 106, Bureau of Entomology, U. S. Dept. of Agriculture PLATE X.
THE IGUANA TICK, AMBLYOMMA DISSIMILE, AND THE GULF COAST TICK, AMBLYOMMA MACULATUM.
Amblyomma dissimile: Fig. 1—Unengorged larva. Fig. 2.—Unengorged nymph (balsam mount). Fig. 3.—Male, dorsal view. Fig. 4.—Unengorged female, dorsal view. Fig. 5.—Fully engorged female (alive). Amblyomma maculatum: Fig. 6.—Unengorged larva. Fig. 7—Unengorged nymph (balsam mount). Fig. 8.—Male, dorsal view. Fig. 9—Unengorged female, dorsal view. Fig. 10.—Engorged female, dorsal view. (Original.)
THE IGUANA TICK. 133
At a mean temperature of 86.5° F. larve which engorged upon a tortoise molted as soon as the seventh day after dropping. How- ever, the greatest number molted on the eleventh day. At a mean temperature of about 83.5° F. larve engorged upon bovines required a minimum of 10 days from dropping to molting, the greatest num- ber molting on the twelfth day. Thus it appears that larve engorged on warm-blooded and cold-blooded animals have approximately the same molting period. A total effective temperature of at least 305° F. appears to be required for the molting of larve.
TaBLE LI.— Molting of engorged larve of Amblyomma dissimile.
| | | | Temperature from dr | | Engorged larve pore gale follow- | vine le date Sele iw Date ideas i a | Total | molted. engorged | = Host. | Num- | ; ——\ number a ber | [|| [motte bs 7 | 9} 10} 11 | 12) 183 14 | 15 | 16 Max. | Min. daily | | | | | Mean. | ice Oy ate a oe ee Se So ee 1908. | | | Fe ay oe er July 6| Bovine... 11] 0| of o| 2| 5| 1] 2] 0| of w| 94) za | 93.29 tales © 7 he .do.... 24| 0} of 1] 5|13| 2] 1] 0} 0 22 94| 74 83. 45 oy Ath aoe. | 35] O} 0] O; 8] 9] 7] 2] OF O 26 94) 74 83.7 Salye, 49.15 db.. | 28] 0} Of. 01.0), 0] 2) 0),0] @ 21 95} 74 84. 09 Aug. 2] Tortoise --| 6| 0] O| 0; 4] 2] O| 0} 0} O 6 9) 73 86. 37 Aug. 3] Toad...... 8| 0] 0] 0] O| O| 7] 0} O 0 | 7 99| 73 86. 51 Do....| Tortoise..| 3] 0| 0| o| 3| of o| of of o| 3 99 7 86. 41 ees a eee } 12] 0} 2] 5] 3] 1] 0} Oj 0} O 11 9) 7 86. 14 Aug. 6 |..-do. 4 iit | a a ae) 2) 8) Oy ay 8 17 | 99| 7 86. 59 Aug. 7 |--.-do. | 2} O| O| Oo; 1] 1] O| O 4 0 2 | 99| 73 86. 94 oe So 3/ 0] o| 1] 2] 0} O| 0} O| oO 3) | 7 86. 30 Aug. .15 | Bovine...) 1| o| of of 0| o}| o| 1} 0} -0 i) =696| 75 84.32 Rae 16 |. do | aT el) ot Oo) Oy. er Oo) ft) fie 21 96| 75.5| 84.17 Aug. 17 |..-do...... 3) 0| 0} 0} O| 0} oO} 1) 2] 0 3} 96) 75.5] 83.90 Due 18}. .do..--.. 3 0 | 0] 0] 0} O} oO} 0; 1] 1 2) 93| 75.5] 83.61 Total. | fae. a2 | ae = Sel ina Al tweaks. we ieee idigagnaens nade
1 Some specimens in this lot were destroyed before they molied.
The nymph (Table LILT).—In order to determine the longevity of nymphs, five lots, each containing several specimens, were kept in tubes on moist sand in the laboratory. The longevity of these lots varied from 86 to 130 days. Those which molted J uly 20, 1907, were all dead by October 26, 1907, or 95 days after molting. One among those which molted August 13-15, 1907, lived between 124 and 130 days; one of the lot which molted August 15-16, 1907, lived between 104 and 111 days, and one of those which molted August 29 to Sep- tember 3, lived between 108 and 122 days.
The shortest period in which they engorged on a bovine was 5 days, the greatest number dropping on the sixth day. In August, 11 days were required for engorgement upon a tortoise, the greatest number requiring 13 days. It appears from these two tests that nymphal engorgement is much more rapid on warm-blooded than on
cold-blooded animals.
134 LIFE HISTORY OF NORTH AMERICAN TICKS.
TaBLE LIT.—Engorgement of nymphs of Amblyomma dissimile.
Nymphs dropped engorged—days following application. Total Date be SR SB AR SAS ES ke A A Ae Ne a a eR ETE myepes Host. ber applied. 9 drop- 5 6 7 8 9 iil 12 13 14 ped. 1908. Aug. 1] Bovine.... if 6 il 2 0 0 0 0 0 10 Aug. 8 | Tortoise... 0 0 0 0 0 1 1 4 2 8
The molting of 28 individuals was observed. In August, at a mean temperature of 83° F., molting commenced in 12 days, the ereatest number molting from the fifteenth to seventeenth days. An effective temperature of at least 479° F. appears to be required. There is no marked difference in the periods required for the molting of nymphs engorged on warm-blooded and on cold-blooded. hosts.
The adults—Seventy-one per cent of the 28 individuals which molted to adults were females. On June 2, 1908, 4 males and 5 females which were slightly engorged were collected on an iguana. The last female of this lot died between July 18 and August, 1908, while one of the males lived until October 9, 1908, a period of 129 days. In a lot consisting of 1 male and 2 females which molted Sep- tember 5, 1908, the male showed the greatest longevity, living 103 days, although it was very weak for over a month prior to its death. A female which molted September 13, 1908, lived about three months in a pill box under very unfavorable conditions.
Numerous attempts were made to get males and females to attach to a bovine, but all failed, and it is probable that as adults they never attach to warm-blooded hosts. On July 2, 5 females and 1 male were placed upon a box tortoise and all readily attached. On the second day following, 2 females had detached and were missing, appar- ently having been eaten by the tortoise, and on the following day a third female was also missing. The male and remaining female which were attached at the anterior part of the body of the tortoise remained attached until July 26, when the male was found to have reattached at the anterior part of the host’s body. On July 27 the female com- menced engorging and the following day the male was missing. On July 30, 28 days after attachment, the female had become fully en- gorged and was removed in order that it might not be injured or lost in dropping. This tick measured 14 by 9by 5mm. During attach- ment no signs of mating were observed; however, as eggs deposited by the female hatched, it is probable that the tick was fertilized just prior to the date that it commenced to increase noticeably in size. It thus appears that mating continues for only a very short time.
. ‘The position at which the female attached and engorged was just
ee See ee ee ee ee ee et ee ee
THE GULF COAST TICK. 135
beneath the carapace midway between the head and the left fore leg. Newstead reports 3 females to have engorged on a toad in 14, 17, and 23 days, respectively.
LIFE CYCLE.
Larve may live 95 days in summer and fall; they engorge as soon as 4 days and in summer may molt as soon as 7 days, at least 305° F. of effective temperature being required. Nymphs may live as long as 130 days during summer and fall; they engorge as soon as 5 days after attaching to a host, and may molt in 12 days after dropping, 479° F. of effective temperature being required. Among the indi- viduals which we have observed to molt from nymphs, there was a predominance of females. Adults may live 129 days; they may engorge in 14 days, commence ovipositing 6 days later, and deposit as many as 1,784 eggs. In summer eggs may hatch in 27 days, 1,133° F. of effective temperature being required. The longevity of all stages of this tick appears to be shorter than any of the Amblyom- mas studied by us with the possible exception of A. tuberculatum.
ECONOMIC IMPORTANCE.
So far as is now known this tick is of no economic importance. However, a better knowledge of the host relations of the species may show it to be of some importance.
NATURAL CONTROL. No natural enemies of this tick have been found by us. THE GULF COAST TICK. Amblyomma maculatum Koch. DESCRIPTIVE.
The common name of this species is given because of the prevalence of the tick along the Gulf coast.
Adult (Pl. X, figs. 8-10).—Males from 4 by 2.25 mm. to 6 by 3mm. Females, unengorged, 4 by 2.25 mm. to 5 by 2.33 mm.; engorged, from 14 by 10 by 7 mm. to 18 by 13 by 8 mm. Males dark brown, scutum brown, lineate with silvery white, lines more or less connected. Unengorged females dark brown, scutum silvery - white behind, brown in front, with one median and two lateral inter- rupted stripes. Engorged females leaden gray.
Nymph (Pl. X, fig. 7).—Unengorged, about 1.33 by 0.75 mm.; engorged, about 4.5 by 3 by 2mm. Dark bluish gray, shining; some of the engorged nymphs are dull white, due to the ingestion of lymph. Capitulum 0.392 mm. long (from tip of palpi to base of emargination of scutum); scutum 0.617 mm. long by 0.598 mm. wide.
Larva (Pl. X, fig. 6).—Unengorged, 0.617 by 0.402 mm. to 0.631 by 0.416 mm.; engorged, 1.5 to 1.66 mm. long by 1 mm. wide.
136 LIFE HISTORY OF NORTH AMERICAN TICKS.
Color brown, lateral margins of scutum with a dark red marking. Some engorged specimens are pink colored at the time of dropping; a few are dull white, but the greatest number are dark gray. Capitu- lum 0.136 mm. long (from tip of palpi to base of emargination of scutum); scutum 0.23 mm. long by 0.33 mm. wide.
Egg.—Ellipsoidal, brownish yellow, smooth, shining. The maxi- mum size of 10 eggs measured was 0.539 by 0.385 mm., minimum size 0.508 by 0.400 mm., and average size 0.520 by 0.397 mm.
HOST RELATIONSHIP.
The type host is not known. Records of 49 collections have been made in Texas and Louisiana by agents of the bureau. Of these, 12 were on dog, 11 on cattle, 8 on horse, 7 on meadowlark, 3 on sheep, 2 on goats, 1 on man, 1 on wolf, 1 on fox, 1 on quail, 1 on red-winged blackbird, and 1 on jack rabbit. A deer and a beetle have also been recorded as hosts. The larve of this species have not been collected by us on hosts in nature. Birds probably act as hosts for the larve and are undoubtedly common hosts of the nymph. Of the above-mentioned collections, the seven lots of this species on meadowlarks and the last four lots listed were all nymphs. Cattle and dogs appear to be the most common hosts of the adults, although, as is indicated by the host list given above, the species has no decided host limitations.
GEOGRAPHICAL DISTRIBUTION. (Fig. 10.)
The type locality is “Carolina.” The species occurs commonly along the Gulf Coast from Cameron Parish, La., to the Rio Grande in Texas. It has been taken inland as far as Columbus, Victoria, and Laredo, Tex. A single male was collected on a dairy cow at Dallas, Tex. No cattle had recently been brought to this dairy from other points. Five lots have been collected by agents of the bureau on dogs at Orlando, Fla. The Marx collection contains a male specimen (labeled by Marx) from Tulare County, Cal. The Marx collection also contains a male and an unengorged female, labeled Memphis, Tenn. It seems quite probable that in these two latter instances the ticks were carried on cattle which were shipped inland. Prof. H. A. Morgan has called attention to the fact that the ticks collected by Niles (1898, pp. 28, 29) in Virginia and referred to as Dermacentor occidentalis belong to this species.
Outside of this country this tick is known to occur in Mexico, Jamaica, Ecuador, Peru, Brazil, Paraguay, Chile, and Argentina.
THE GULF COAST TICK. 137
LIFE HISTORY.
Observations on the biology of this species have been made by Lahille (1905), Hunter and Hooker (1907), Hooker (1908), and Newstead (1909).
Fic. 10.—The Gulf Coast tick. Amblyomma maculatum: Distribution in the United States. The large dots show localities where the species has been collected in our investigation. The small dots indicate the probable range of the species. (Original.) \
The egg (Table LIIT).—In May and September at a mean temper- ature of 74° F. oviposition commenced as soon as the third day after dropping. The largest number of eggs deposited by any one of the seven females observed was 11,265, the smallest number
188 LIFE HISTORY OF NORTH AMERICAN TICKS.
4,560, with an average of 8,282. The female which deposited the maximum number of eggs measured 17 by 12 by 6mm. ‘This female began depositing on the third day after dropping (September 1, 1907), and deposition was completed in 16 days, 1,793 eggs having been deposited on one day. The individual which deposited the smallest number of eggs was the largest tick observed by us, measuring 18 by 3 by 8 mm. The cool weather which followed the dropping of this tick caused an interrupted and prolonged period of deposition and a considerable reduction in the total number of eggs deposited. Four females, engorged on a bovine, measured 14 by 10 by 7 mm., 18 by 11.5 by 8 mm., 15 by 10.5 by 7'mm., and 18 by 12 by 7 mme respectively. Others were engorged on a horse and ona sheep. The preoviposition period varied from 3 to 9 days and the deposition period from 13 to 75 days.
The minimum incubation period in May at a mean temperature of 81° was 21 days. An effective temperature of 793° F. appears to be required for embryonic development. .
TaBLE LIII.—Incubation and larval longevity of Amblyomma maculatum.
Temperature during incubation. Eggs de- foun’ ee All larvee Larval posited. egan. we dead. , | longevity. Sees period. . sos Average Total Maximum. | Minimum. daily mean.| effective. 1908. 1908. Days. 1908. Days. SER Sis earae as May 20] June 10 22 | Sept. 24 107 90 68 79.5 803. 25 - May 21 | June 11 2 isa Omecierae 107 90 68 79.2 797. 25 May 30 | June 19 7 Nees Ko ee 98 91.5 69 81 793. 75 1909. 1909. Nov. 25 | Mar. 6 102 | June 6 92 87 17 59. 22 1,654. 00 1909. Oct. 8 | Nov. 28 52) | Mar. . 1% 116 94 41 70. 05 1, 406. 50 AT OUTDOOR TEMPERATURE. 1906. 1906. 1907. Sept. Oar OC Gn|enss— "ase Feb. 18 TBO Cees ee ea ones ale oes ae eee ae Sept: Wien. Goer -.4| eta ee rye" Abr. 1 TOE ae See oe soe eee ke REET ee ee Pee - Sept., (9) |/22-G02---- 235 dane 23 110 95 42 77.4 963. 20 1906. Sept. 11}: Oct.- 7 27 | Dec. 8 63 95 42 76. 68 909. 36 1908. 1908. 1909. Aug. 23 | Sept. 16 24 | Mar. 3 168 100 59 83.4 969. 60 1909. Oct. 3] Feb. 20 141 | June 8 108 89 10 60.98 1,201. 65 OCH 2 2 = GOs seh 142 | June 17 117 89 10 61. 01 1,224. 25
THE GULF COAST TICK. 139
TaBLE LIV.—Engorgement of larvx of Amblyomma maculatum.
Larve dropped engorged—days following application. = SSeS ee eee Date ome ap- Host. | number Cie a | eo 6) 6 Le | eb 8 ton eee 1906. CYC Se ee aioe BG ee cae ae 0 0 0 0 1 0 0 9) 0 0 1 190 Ube oases heidisians Bovine 0 0 1 65 23 1 0 0 0 99 (QV? UUs Ge eee Owns sts 0 0 @ | °@) 29 7 3 0 0 0 39 1908. LNs S27 Ge ae eee do 2ass< 0 0 ye ee Ia 51 0 0 0 0 0 167 MUR Gun Ata nie ec, cie coe 2 Ow ee =e 0 0 0 3 14 2 0 0 0 | 0 19 ‘it 172 a eer ea GO che 0 0 0 J 13 if J 0 0 | 0 16 BREEN ES. os odid.acoes spre Gow. 0 0 0 0 2 0 0 0 | 0 0 Z
1 Larvae which molted on this day were included with those which molted on the following day.
At a mean temperature of 85.7° F’. molting began as soon as 7 days. One of 7 larvee which dropped November 4, 1908, molted 121 days later. The mean temperature during this period was about 60.8° F. An effective temperature of at least 299° F. is required for molting.
The nymph (Table LV).—There are no records at hand on the longevity of the free nymph.
Engorgement took place as soon as 5 days, 75 per cent dropping on’ the sixth and seventh days after attachment. The longest engorge- ment period observed was 11 days. The tick upon which this record was made was collected on a meadowlark and placed upon a rabbit about a month later, when it readily attached.
TABLE LV.—Engorgement of nymphs of Amblyomma maculatum.
Nymphs dropped engorged—days following application.
a CAL a SoS hho ee Total aeieat 4 Host. number die we ee ow eee ge hg) ge | ag [gy fEOpDEs | ———E4 ee eee 4 = Oct. 27, 1907..| Dog...... a fines ol 68) of. a| of of. of -e 2 ole, 1007-.) Bovine...|/ 0] 0). 6) oF 38) o8|--5 1 ate 5 aoe 17 Nov. 1, 1907..| Dog...... CP ow at wld pole? Gt.. Ol) Ae 1 Aug. 11,1908..)} Bovine... 0 0 0 0 0 3 | 0 0 0 0 0 3 Mar. 27,1909.) Rabbit...|. 0| of; O|, O| Oo} oO} of}; o| oj. oO | 2 i |
The shortest molting period recorded for nymphs is 17 days. This record is based upon specimens which dropped August 17, 1908. The mean temperature was 84° F. and the total effective temperature 694° F. during the period. There was considerable variation in the molting periods of ticks dropped in November which were kept under nearly the same conditions, the shortest period being 51 days and the longest 71 days.
The adult (Tables LVI, LVII).—Two-thirds of the 24 adults, the molting of which was observed by us, were females. The greatest
140 LIFE HISTORY OF NORTH AMERICAN TICKS.
adult longevity recorded was between 388 and 411 days. These ticks were kept on moist sand in the laboratory. The longevity of the sexes appears to be about the same.
TaBLeE LVI.—Longevity of adults of Amblyomma maculatum.
Molted. Longev- Date last tick died. ity in Date. Male. Female. | Total. days. 1907 1908 Decembene. 5 a ae es te eee a 2 2 A) Deei Gt saeco tee 2 eee 365+ WM ECIB OF ae wate ew 2.05 ey Cie il il 2 Jan. 22-heb-s14.- eae 388-411 1909 1910 14 Cpe REN Se eR EE, yey ey Oe 1 0 Ao ONOVi: 282. ce Soe 2 May i4=5 ace eee. ese as See ee Se Se 1 1 2 | Sept. 26—Oct. 18......- 144-167 MOS apap ee a oe eae 0 1 | (Sept..26e. 6 a. 20. at eee 144
Males and females that had been reared from nymphs when placed upon the host attached quite readily. Twelve days passed, however, before they were found in copulation. After a male mates with a female it usually remains with her until she drops; it then goes in search of another mate. Mr. J. D. Mitchell states that he has observed the sexes in copulation after having been removed from the host.
Engorgement has been found to take place as soon as 14 days. Partially engorged females reattach if they have not been injured in being removed. The largest specimen which we have observed was collected partially engorged from a sheep; it reattached and engorged upon a bovine. This specimen remained attached for a day and a half after being apparently fully engorged. Upon removal it was found to weigh 1 gram and to measure 18 by 13 by 8mm. Next to Am- blyomma tuberculatum this is the largest species that occurs in the United States.
TaBLeE LVII.—Engorgement of females of Amblyomma maculatum.
Females Period of
Adults applied. Host. dropped attach- Size engorged. engorged. ment. 1908 1908 Days. NY) RO (Re ages SER Ose eres) < AEN ri ie Bovine May 11 14 | 14 by 10 by 7mm. ye Ne eee BAN SP eee Pe oe Serle Ofseace May 12.... 15 | 18 by 11.5 by 8mm PANT 21d) = cesses | casei cee a ee ee aes doeeeees May 14 (2) 17 | 15 by 10.5 by 7mm SALPT Dike cies ch AEE Ss A ee Ee donee May e15t 2. 18 | 18 by 12 by 7mm
Males remain attached for long periods after the females drop and may mate with several females. This habit of remaining upon the host after the females have dropped accounts for so many males being taken at certain seasons of the year when females can not be found. On August 28, 1907, Mr. J. D. Mitchell of this bureau examined the ears of 340 cattle at a branding chute in Goliad County, Tex., and found 4 females and about 100 males, none of these being in coitu. The males were frequently in clusters, as many as 9 being counted in
THE GULF COAST TICK. 141
one cluster, 5 or 6 being a frequent number. The following day Mr. Mitchell examined the ears of 933 cattle in Refugio County, Tex., and found 15 females and several hundred males. In two instances specimens were found in coitu. Many of the males were in clusters of from 5 to 10. In another locality 567 cows were examined, 1 female tick and 3 males being found, all on different animals. Our records show that males were removed from hosts a month after all the females had dropped, and it is probable that they remain on the host fora number of months. As with some other species, the males, having once fed, do not appear to live long after leaving the host. Thus 2 males removed from the host a month after the females had dropped lived less than a month, one dying in 10 days, although kept under the most favorable conditions.
This species attaches largely to the head, particularly to the ears both on the inside and outside.
LIFE CYCLE.
Larve may live for 6 months during the winter and for 112 days in summer; they engorge as soon as 3 days after application to a host and molt as soon as 7 days after dropping. A total effective temperature of 399° F’. is necessary to produce this molt. Nymphs engorge as soon as 5 days after application and molt as soon as 17 days after dropping, a total effective temperature of 694° F. being required to produce this transformation. Adults may live for 388 days; they mate upon the host, may engorge as soon as 14 days after attachment, and begin ovipositing the third day after dropping. Eggs hatch as soon as 21 days after deposition, a total effective tem- perature of 793° F. being required for incubation. Although adults may be found at any time during the year they appear to be much more numerous in the summer and early fall than at other seasons. The nymphs are to be found .in considerable numbers upon birds in February and March.
ECONOMIC IMPORTANCE.
In the sections where this tick occurs in any numbers it is the source of great annoyance to domestic animals, particularly to cattle. By attaching to the inside of the ears, as frequently occurs, great irritation is caused; in the case of calves, this irritation is sufficient to cause suppuration and the formation of large scabs. The injury in the ears furnishes opportunity for the screw-worm fly (Chrysomyia macellaria) to deposit its eggs, which in the case of equines some- times results in the destruction of the cartilage, thus causing the ears to droop—a condition known as “‘gotched”’ ears. The species is also of some importance on account of the fact that it sometimes attacks man.
NATURAL CONTROL.
The natural enemies of the cattle tick undoubtedly destroy many
ticks of this species.
142 LIFE HISTORY OF NORTH AMERICAN TICKS. ARTIFICIAL CONTROL.
The longevity and numerous hosts of this tick make starvation impractical. Where the injury is sufficiently great to warrant arti- ficial checks, hand picking, mopping, or dipping should be resorted . to. Animals should be treated as often as every 12 days in order to prevent the females from engorging.
THE LONE STAR TICK. Amblyomma americanum (Linnezeus).
This species receives its common name from the silvery spot on the apex of the scutum of the female.
DESCRIPTIVE.
Adult (Pl. XI, figs. 2, 3, 5-10) —Males from 2.5 by 1.5 mm. to 3.5 by2.5mm. Females, unengorged, 3.5 by 2 mm. to 4 by 2.25 mm.; engorged, 10 by 9 by 5 mm. to 15 by 12 by 8 mm. Color brown; posterior lobe of the scutum of the female with a large silvery white spot; the dorsum of the male also has silvery white markings around its posterior margin.
Nymph (Pl. XI, fig. 4)—Unengorged, about 1.5 by 1.25 mm.; hight brown, with much yellow (fulvous), scutum somewhat darker; the intestines, which show through, appear to be of a dark brown color; length of capitulum 0.41 mm. (from tip of palpi to base of emargination of scutum) ; scutum 0.86 mm. long by 0.699 mm. wide; engorged, about 4 by 2.5 mm. in the larger specimens, which usually ~ become females, and 3 by 2 mm. in the smaller, which usually become — males; color dark gray. The silvery white markings of the males and females do not become visible until a day or two prior to the shedding of the skin.
Larva (Pl. XI, fig. 1)—Unengorged, 0.64 by 0.51 mm.; length of capitulum 0.185 mm. (from tip of palpi to base of emargination of scutum) ; scutum 0.235 mm. long by 0.832 mm. wide; body ovoid, brown, lateral margin of scutum darker brown. Engorged,1.5 by 1 mm., ovoid. Most of the larve as they drop engorged are dark brown, eae but some have a pink color.
qq Bllipsoidal, yellowish brown to pale yellow, or pale brownish yellow, shining, smooth. The maximum size of 10 was 0.570 by 0.431 mm.; minimum size 0.514 by 0.416 mm.; average size 0.544 by 0.419 mm.
HOST RELATIONSHIP.
THE LONE STAR TICK. 143
of the United States, largely in Texas, the frequency of occurrence on different hosts was as follows: Dog 23, cattle 11, man 9, horse 9, deer 4, goat 3, peccary 2, hog 2, mule 2, skunk 2, sheep 1, wolf 1, fox
Fig. 11.—The lone star tick, Amblyomma americanum: Distribution in the United States. The large dots show localities where the species has been collected in our investigation. The small dots indicate the probable range of the species. (Original.)
squirrel 1, badger 1, domestic cat 1, wild turkey 2, and chaparral cock 1.
GEOGRAPHICAL DISTRIBUTION. (Fig. 11.) The type locality for this species is Pennsylvania or New Jersey. The Marx collection contains one unengorged female from Labrador. The species has been collected from nearly all of the States bordering
144 LIFE HISTORY OF NORTH AMERICAN TICKS.
upon the Atlantic Ocean and Gulf of Mexico and from several inland States, including Michigan, Kentucky, Missouri, Arkansas, and Oklahoma. It is also reported to have been collected in Guatemala, Guiana, and Brazil. The species is very abundant in a large part of the States of Texas and Louisiana.
LIFE HISTORY.
Information on the biology of this species has been published by Leidy (1891), Morgan (1899), Hunter and Hooker (1907), and by Hooker (1908).
The egg (Tables LVIII, LIX) —In the laboratory in June at a mean temperature of 87 7° F’. oviposition commenced as early as the fifth day from dropping, while out of doors in July and August at a mean temperature of about 81° F. seven or more days were required. The longest preoviposition period recorded was 13 days. At a mean temperature of 80° F. one tick continued oviposition for 23 days. This individual, however, was one of the largest met with (measuring 15 by 12 by 8 mm.) and deposited the maximum number of eggs recorded for the species, namely, 8,330 eggs between May 25 and June 16. The maximum, minimum, and average preoviposition period for 12 ticks, the deposition of which is recorded in Table LVIII, was 9,5, and 7 days, respectively. The maximum, minimum, and average oviposition period for these ticks was 23, 8, and 13.25 days, respec- tively, and the average number of eggs deposited was 3,053.5 per tick.
TaBLeE LVIII.—Oviposition of Amblyomma americanum.
Number of eggs deposited—days following dropping. | Date engorged female 4 dropped. | | | | | Gi 8 | 9 OP |e et UPA Ales a8} 14 15 16 17
: 1906. PPD 20 a ci2ro2 sw steer ete 0 0} 110 74 31; 118 89 | 230] 399} 503 | 464 338 Mayle o.2:22).dee seciesae 0 0 0 0| 178) 383] 583} 213] 465 | 356) 230 73 DOs 220 oh eee eee 0 0] 390 | 417 | 656} 835] 963 50 1 572 | 229 201 WD O)cening ose Soe eee eee 0} @Q) 414} 285] 504) 594) 361] 210) () 156 66 55 DO) Fe SS eco Sawa ite 0 O >}, 193") 801}; 409°) 271 | 197 82 | (1) 144 24 64 DO... 8 sagas 0 0; 180) 187) 209) 144 99 57 | () 53 14 4 DOs. 2c sse. - See ee 0 0 58 | 206] 380} 368] 187 53 | (2) 118 36 36 Ono: 2 ce 2 eee ee 0 0 42 | 201} 307/] 264|] 197; 110) @Q) 89 41 39
1908. MaViGr acini: Je ae occa eee 0 0 0 0 54 | 485 | 464] 501] 496 | 622 | 323 342 Dale ah opie maiss Boe 0 0 0 0 32 | 445 | 439} 589) 248 | 745 | 219 239 Miaiyarcreess Staple tt evsh wees Bo 0 57 | 270 | 265 | 367 | 335] 420| 354) 364] 330] 195 67 Mayiil 9s. fox ees ewe scans (4) 460 | 757 | 766} 805| 730}; 808| 714] 647} 615] 467 635
1 The eggs laid on this day are included with those recorded under the following day.
THE LONE STAR TICK, AMBLYOMMA AMERICANUM.
Fig. 1.—Unengorged larva. Fig. 2—Unengorged female, dorsal view. Fig. 3.—Male (balsam mount). Fig. 4——Unengorged nymph (balsam mount). Fig. 5.—Male, dorsal view. Fig. 6.—Engorged female, frontal view. Fig. 7.—Male, ventral view. Fig. 8—Unengorged female, dorsal view. Fig. 9.—Unengorged female, ventral view. Fig. 10.—Fully engorged female, dorsal view. (Original.)
THE LONE STAR TICK. 145
TasLe LVIII.—Oviposition of Amblyomma americanum—Continued.
Number of eggs deposited—days following dropping. Total
Date engorged female a Se ee ee ee ee ee ae eee ee eee drop na ber of 18 19 20 21 22 23 24 25 | 26 | 27 / 28 | eggs. 1906. si / TM eS eee eae 212} 132] 112 70 US Ge ees PE A a ee 2,882 te ye ESE ate eee ee 0 0 27 Up) Sa", SES Bee Bees, ee” ees 0 at el (eee 2,508 oe cae Ea | 148] 129 0 Oo 8 Se aad, AINE aS a Wil 4,590 Li Lot {2 Ee ee 14 0 0 if ie ie! Sepa eee Pape meee eee Bas Vee Bae 2,659 _. een pate enema 25| 17 6 3 St 5c CG ERG SONNY Salts UES 1,736 haters 2 0 <% eei22s, 3 J) 0 0 0 UE RS UR) Sa ee ee es aS Bee ed 947 5 eS ee te SE Bee ee 25 20 16 5 2 yess Shee. ee! oa Ae 1,510 i. ee So Sere eee ee 6 10 0 OU [iia 32k el PBS pale? ERED 1,306 1908. | | 1 eee eee 196} 103} 106 90 19 0.) -Deadt: he. 1 2s} e- | 3,751 Phe ER et 162| 54 2 i) 0 ag ee i eae clon he fe Bisel 3,174 _ Se ae 74| 67] 7 5 0 ee ee OSs es tiem 3,249 LT gt See eee eee 186 | 203; 153) 100 76 58 51 | 38 | 25 | 22; 14) 8,330 ‘eS ae eo a ones ENS ges ae Rae eee | 3,053.
The minimum incubation period recorded occurred in the labora- tory in June and July at a mean temperature of 80.5° F. This period was 23 days, while out of doors in July and August, at a mean temperature of 82.5° F., 32 days passed before hatching commenced. The total effective temperature required for embryonic development appears to be 862° F.
TaBLE LIX.—Preoviposition, incubation, and larval longevity of Amblyomma
americanum. | | Temperature during | incubation. Mini- Date en- or E Hatching | um jf Larval Total emale | deposited. began. ncn: | All larve dead. Dacely aveleee p ied Maxi-| Mini-| age | tive mum.}mum.| daily | tem- mean.) pera- ture. 1906. Days 1906 Days OF Were ee oe May 28, 29...| Before Joly ic5 {2- S| RW hs ld ro ee eee 1 i |) Pe Pere rk aia | Wale May 30, 31...| July 1 or before... .- See APRN aches seers ners Sea Bah to =e ee os A ee 1907. 1907. 1907. | Mar. 30..| Apr. 12......| June 13...... ol Bree I Ge Seema DALI Ria Aad oat June 18..| June 25...... July 22...... he ape Re Wek BES ene Te 3 1908. 1908. 1908. May 14, 18...) June 11...... 29 | Sept. 30—-Oct. 7........ 110-115 | 89.0 65 | 78.5 | 1,028 May 19-27. June 15 7 OS ti | 123-131 | 91.5 68 | 79.7 | 1,018 May 27-29...| June 21.... 26 | Before Sept. 24........ 95 | 91.5 69 | 80.4 972 = Peat June 24 26 | Sept. 30-Oct. 7......--. 98-105 | 91.5 69 } 81 986 a -_ June: 3... cue Pi Geen eee oe , 91 | 91.5 69 | 81.2 | 1,019 June 4-6.... | June 29..... 26 | ‘Oot. 26. 5.0... eee 119 | 91.5 69 | 80.8 983 1909. 1909. 1909. ! 1909. June 4...| June 10......| July 4...... Beat ere eee ee eee a ea leas ca dad 91.0 69 | 80.2 930 June 11......| July 3....... 23.| Sept. 2-15............. 6l— 74 | 91.0 70 | 80.5 862 June 9.......| July 3......-. 25 | Aug. 20-Sept. 2........| 48- 61 | 91.0 69 | 80.3 932 June 9.../ June 15......| July 9....... 25 | Sept. 4-16.........-.-. 57- 68 | 90.0 71 | Sl 950 1910. 1910. Sept. 27..| Oct. 11...... wont Pac ce ke 109 | May 20-July 16........ 113-170 | 87.0 17 7.1 | 1,908 ek. 2. ..| Oct. 14...*.. i a GOR eS 117 | July 16-Aug. 2........ 159-176 | 87.0 17 | 56 1,949 1908. 1908. 1909. 0 July 14... Agr Task 1S 279 | 97.5 60 | 82.3 | 1,256 1) wuly 16°... *. AG 10-.* 32 | Jan. 28—Feb. 8......... 196-207 | 97.5 60 | 82.5 | 1,262 @) eal yi7...... Are VT 2 32 | Dec. 24 (1908)-Jan. 23 .| 160-190 | 97.5 60 | 82.5 | 1,264
1 Records made out of doors.
21448°—Bull. 106—12——-10
146 LIFE HISTORY OF NORTH AMERICAN TICKS.
The larva (Tables LIX-LXI)—As is shown in Table LIX, the greatest longevity of larvee observed by us was 279 days. This record was made on ticks kept in a tube in a protected place out of doors. The longevity of larve kept in the laboratory did not exceed 176 days and usually ranged between two and four months. Larval engorgement was completed as soon as 3 days, the greatest number dropping from the host on the fourth day. The longest period required for engorgement was 9 days; this, however, may be explained through the failure of the ticks to attach at once or because they attached at a point where the blood supply was poor.
TaBLe LX.—Engorgement of larvxe of Amblyomma americanum.
Larvee dropped engorged—days following application. Total Date larvee applied. Host. number dropped. Pape2 eS Teas Ge Eee S es9 Julbyet2 A907 .3 (psd: sas onaseeer eee es Bovine? 25); Oe On Sa Lie lieedal. OF| One Onan 0 264 Aor 26 1908, Anp. makes Sees ssa SranGOL Sacco) OMe OM 1OMIERON RG ahe Gul) Orth 2ulwe deka 15 Duby 27; AOS corp Wesco cei see oe Soe COW see OF Oo O80 Tel Os SOR ON On O 93 AUS SILOS toNp- wiles Loerie ods 28 Rabbit. 222) 70) 0 F710) 60 |, 215) 103) e465) KOF |) Oy 20 96 SURG OOO est ees cick Oe eo eae ae! Bowness.) 10.0.) O05) 200 115) 105), On iOS On a0 21
The rapidity of engorgement is shown in Table LXI:
TaBLe LXI.—Rapidity of engorgement of larve of Amblyomma americanum applied to bovine at 3 p.m., July 12, 1907.
Period
frail Per cent Date engorged larvee dropped (bags examined). Number. aaniie of total pplica- | gropped tion. pped: \ 2 HO Hours. Sui seat bs a Is oye ee, Ce Ree a ee RG eee See erie See aa ee 26 68 9.8 JULY: LDVS PMs ss acise see tee lable Seisorac Weeks Se BE ices Ee ete ee openers 51 72 19.3 Sulive 5, 4.30 MM. 8520 eae hast es ck ae aes -eoeee os sae ee see = 3 734 1.2 sitTy GS UO ea ea estate evi Nee ca ees ey are geste el caper gre reg tre SR 104 91 39.4 Fee LG; st 30 yp oe, ae eR ee ee oe revere yeh ene i eee ne eat 69 944 26.1 RUT UG be BINS ae Sor ate ae SO te een ee ree AE eee eet eee ieee eee te 4 974 1.5 Sly Li LO aims. oh yak care chek o = 2 ieieidy sy Sialala, Sete Soe eee Sy oie eae 5 1143 1.9 JULY? L752 Ds WS So fo Sd akoe is a eitel gisele ae Sane ew 2 I er cereals ie ae yey yee oe 2 1183 8 July 17; PMs fe Bes ewe se soos eke Sete enioe heen oe aie eran eae ae 0 eee eee ee ee a eel mE RB MiP en cianicht lp deca ah Wl A 204 |
Our observations of the molting of engorged larve were made on 326 individuals. In July and August at a mean temperature of 86.78° F. molting commenced in 8 days. A total effective tempera- ture of 350° F. appears to be required for this transformation. The longest period recorded from dropping to molting was 26 days. During winter this period would undoubtedly be much longer.
The nymphs (Tables LXTI-LXIV).—The most complete informa- tion at hand on the longevity of nymphs was obtained in an experl- ment in which 30 nymphs that molted June 23-26, 1907, were kept out of doors in a tube that had a cork stopper, through which a small hole had been made and a small glass tube inserted to permit
-
THE LONE STAR TICK. 147
an equalization of the humidity content of the air. Over the small glass tube a cotton cloth was tied to prevent the escape of the ticks. The records show that on May 6, 1908, 6 were alive and very active; from July 28 to August 29, 5 were found alive; from September 3 to September 10, 4; from September 18 to September 23, 3; from Sep- tember 28 to October 1, 2. The sole survivor died on October 11, 1908, a period of 476 days or 15} months after having transformed
to a nymph.
TaBLeE LXII.—Longevity of nymphs of Amblyomma americanum.
z i Pye Nymphal Date molted or collected. | Number. Date last larva died. longevity. b. | Days. anne 23-26) 1907, molied. * ... 2-22-22 -2--5- SO) set ab totes 20 oo tS fae 176 ee tt tm nolted........).. 4... --.----- | mi Soe: 1s, 1008s ‘alive 2 2. 2S 240+ Sept. 2, 1908, molted................-------- | 6 | June 24 to July 13, 1909...............- | 295-314 Sept. 21, 1908, aMgmtCg eee ene LAL = | aa. 30 te Pep 225 1908 Ss ese oS | 131-155 Sept. 91.23, 1908, PLN et 2 Sap eed aes ee ee 4) dan 2? te. Feb 112 1909... 8 5. 2 3 121-144 Aug. 31 to Sept. 1009 -HONieR et: 3353222: as} Mebs ls, 1918 Salive..- . <2. 22 189-196+ Sept. 2, 1909, 8 SE ie OES 10)| Feb.28 to May: 20, 1910... ...:.....-..1 207-260 .
The shortest period in which engorgement took place was three days, the majority dropping from the third to fifth days.
TaBLeE LXIII.—Engorgement of nymphs of Amblyomma americanum.
Nymphs dropped engorged—days followi ing |
application. | Total
Date nymphs applied. Host. number dropped
1/2)3/4/5|]6)/7)]8]9 | |
j |
/ | |
Lae ee ae Dor... 0] Oo] 2} 0] 0O| O| oO] Oo} Of} Oo 2 OO ET a Se eee Bovine.....| 0} 0|14| 3} 0/ O| 0} 0} O| 0} 17 June 15, 1908, 5 p.m Soe Seed & eee Gecear @) St Or ei sr 2) at ba ol eI 3 oe a eee ae do....| 0) O| 4) 8] 7] 0} O| 0; 0} OF 19 aires 1908: So. TN 2. oe Se Rabbit Pe Ore ges he Oe hve se 10 NETS ER a Bull... 0} o| o| o| o 1} 0} 1] O| Oo 2 RTS Ree, aan 2 oie do. 0 Oo 2 0 | iil 6] 3 0 | 0 6
In August, 1907, molting commenced on the thirteenth day. In August, 1908, at a mean temperature of 84° F. molting commenced as soon as 16 days after dropping, a total effective temperature of 657° F. being required. The longest period from dropping to molting recorded was 46 days. Winter temperatures lengthen the molting period considerably.
148
TaBLE LXIV.—WMolting of engorged nymphs of Amblyomma americanum.
LIFE HISTORY OF NORTH AMERICAN TICKS.
Date a ~ engorge um- nymphs Host. ber. dropped. 13} 15] 16 | 17 | 18 | 19 |} 20 } 21 Aug. 3, 1907 | Bovine.---. ie) IANO DI2E ee aa 0/0 {0 59! 3 Auge 41907 | sos. dost ay 2 3 /1g)0 |22;0 |0 10 |0 10 June 16, 1908 | Horse.......- LOM OM ORION Oe eke Om 0 June 20,1908 | Bovine..-....- THO AO ORONO} OF ORK June 21,1908 |..... done wae LO OPP Or Om) 0 130 June 23,1908 |..... dost LS Opa On Ol | Oke Olt Olen Olea 0 Aug. 21,1908 | Dog........-. 4/0 lo |o {i$ )\2¢ 0 |o lo Aug. 23,1908 | Bovine....... 4/0 jo }0 | 39/0 |0 {0 Jo Aug. 24, 1908 |... do. slo jo |o {13 Panera nt Aug. 25, 1908 |..... dates 710 lo |igl 1d) 1g {73 }190 Sept. 4,1908 | Rabbit......- CO NO OO OO 1 3 Sept. 2,1909 | Bovine....... 1210 lo |iglig ve to 0 0 Sept=,1051909)), Bull? . 32-22 LOPS OF 3 ROMO) SIO! 120), 120) 910) Sept. 12,1909 |..... douse eae ZO |Om OMmieOr FO. 180) ie0ee10 Sept. 138, 1909 |..... doz.s cee LAOS 08 |cO IO aI} 20 120) 510 Sept, 15,1909 |.--.. @Osa sees 2 OO OM ON ONS Ont eOns0 Marse21910 |e 2: dOs,..< 0508 EO Oe AO GO Oe Or Mar. 23,1910 |_.... Gonos LO 0m 0 OF 0) 80 0) 310 Motalesa|ee Sec ete 70 [¢=Male. ?=Female.] lted. mists Number molted engorged |Num- nymphs Host. ber dropped. Male. |Female.| Total. ATE 13,1907) se OVANe. 4-4 - e 14 4 8 12 aie) 4 1907: |e. - ats aan ee eee 3 1 2 3 wune' 1651908" | Horse’. eee. 1 0 1 1 June’ 205 1908),| Bovane:-= 2. 22-2 _ = 1 1 0 1 June 21,1908 !..... OR See oeee 1 1 0 1 June 23,1908 |..... Gov cee ee i 1 0 1 u Ane 2119088) Dog: 22-22% 222. 4 1 3 4 Aug. 23,1908 | Bovine-...--.-:.-- 4 0 3 3 Aug. 24,1908 |..... doses 8 6 2 8 Aug. 25,1908 |..... Oe 7 5 2 vi Sept. 4,1908'| Rabbit. ------..-- 6 1 4 5 Sept. 2, 1909 | Bovine-......----- 12 6 4 10 Sept 1051909) | Bulls sees. 1 1 0 il Sept. 12,1909 |....- OOS eee 2 0) 2 2 Sept. 13,1909 |..... Gorers ese 1 0 1 1 Sept. 15,1909 |..... i Sena © SAREE 2 0 2 2 Mar. 2119104) -= Gosa. cee 1 1 0 it Mars 923,910 22-2 GO ser Ae 1 1 0 1 MO CALETA a) ea ee ee ae 70 29 35 64
Engorged nymphs molted—days following dropping.
22|23| 24 | 25 |26|28|31|32] 45] 46 0 0 |}o |o |o lo fo fo Io Jo 0 lo |o |o |o lo 'o jo lo Io 0 lo |}o |o lo lo fo (lo Io Jo 0 lo |}o |o jo lo lo [lo |o (0 0 lo }o0 |o jo jo lo lo Io Io 0 lo |}o |o lo [lo |o lo lo \1¢ 0 lo |o |o lo jo lo jo fo ° 0 0 }o |o p p jo 0 p fo igio |o 10 lo (0 lo 0 lo 0 0 lo jo jo |o lo lo lo |o Jo 19)29{7S\to jo Jo po jo o jo 0 lo |}o |o lo lo lo lo lo (0 0 lo |o |o jo liao jo lo Io 0 jo |}o |290 |o |o fo fo |o 0 lo |o | 1910 |o 'o |o lo Io 0 lo |o |o \o lo l19!1910 Io 0 jo |o Jo 0 jo fo jo jrxo 0 lo |o |o jo lo |o \o \1glo
Temperature from dropping to date first tick molted.
Average
Maximum.| Minimum, daily mean.
VE 5225 ee 90.0 70.5 80. 96 93.5 70.5 81. 52 93.5 70.5 81. 57 99.0 75.0 83. 60 97.5 75.0 83.72 97.5 75.0 83. 96 97.5 75.0 84. 04 97.5 75.0 84. 19 97.0 70.0 81.1
101.0 68.5 86.6 101.0 56.0 79.3 98.5 56. 0 75.6 96.5 56. 0 75. 2 95.5 02.5 75.6 92.0 43.0 86. 2 89.0 43.0 86. 2
The adult (Tables LX V-LXVI1).—The greatest longevity of adults
recorded was between 393 and 430 days.
The longevity records given
below were based upon adults kept in cotton-stoppered glass tubes on moist sand in the laboratory. It is quite probable that the lon- gevity would have been greater had the ticks been kept out of doors.
The females appear to live longer usually than the males.
The first
lot of ticks recorded in the table is the only one in which the last surviving tick was a male,
THE LONE STAR TIOK. 149
TaBLe LXV.—Longevity of adults of Amblyomma americanum.
Number. Date oa hic cal | ReMalel ackel Le SES Date last tick died. Longevity. Total. | Male. | Female Days
mime of LO0RL a. oes so. - 3 2 Dl Cs 26. LOO ee 55 ea et eee 207
Dep tel LOS es Soe cope ake 8 1 | May. 15-June.8,.1900... 2.2822 256-280 Mepis il OOS sss. io. ee 10 6 AY} Jan. 22—Keb: 185 1909 Wo crctwiiesss 133-160 Sept. 26-28, 1908......... 5 1 4} Aug. 20, 1909, 1 female alive....... 326-328-+ Sept. 10-20, 1909......... 11 4 7} Oct 1l8-Novy..14, 1910.2. ..ncccun ce 393-430 Oct. 7-17, 1900... 2 3.22 6 i! 5 Pp Aug. 18-Sept. 26,1910)... 022 cee 305-354
Mr. J. D. Mitchell once observed this species in copulation on herb- age but we have no other record of such a habit. Ticks which have been kept together in tubes have never been observed in copulation. When unfed ticks are placed upon a host, attachment usually takes place at once, the sexual instinct being manifested only after several days feeding. Fertilization may be necessary for engorgement, as females which have been collected from vegetation have attached readily, but in the absence of males have failed to engorge and have died about a month after attachment. Males placed upon the bovine scrotum upon which females of other species were attached have been found in coitu with other species (Margaropus annulatus australis, Amblyomma maculatum, and Dermacertor nitens) even though females of americanum have been attached upon the scrotum at the same time. They have, however, remained in the position of copulation with other species for periods less than 24 hours. The eggs deposited by unfertilized females are dark and shriveled up. Our observations seems to indicate that only a short time is required for the fertiliza- tion of the female as males remain in copulation for a few hours at a time, then pass to other females, or return to the same female. They are frequently found mated with fully engorged females.
Males have remained upon the scrotum for more than two and one- half months, or a month and a half after the females dropped. Fe- males collected from a host, if not more than one-half engorged, will attach to a second host, and if fertilized while on the first host become engorged in a comparatively short time. The minimum period in which engorgement has taken place is found to be 11 days, while slightly engorged reattached ticks which had probably been fertilized while upon the first host completed engorgement in 2 days. The longest period required for engorgement was 24 days. The length of the engorgement period does not appear to influence the size of the engorged female.
150 LIFE HISTORY OF NORTH AMERICAN TICKS.
TaBLeE LXVI.—Engorgement of females of Amblyomma americanum on bovine.
Engorged females dropped—days following application. Total number
Adults applied. = 2}3/41517181 9110] 11] 14] 15 | 16| 20] 24 | dropped.
Mars23 19076 -4p, amt acces Ws Stee Recht evepege (are Soealeeer| ee Mar 22: st90 709 ra scm 2) Soi = eee | ace eee A leer atest Se aloe aes
SSE 1S) LODDTE Sah DIN ee ce | oan ene eS ae Ae
C9 Oot et OT et oD
1 This tick was collected Mar. 25,1907. It was slightly engorged, measuring 5.5 by 4mm. 2 This tick was slightly engorged (5 by 4mm.) and probably fertilized when collected.
3 These were collected on a host but were not perceptibly engorged.
4 This tick was taken from a host and was slightly engorged.
LIFE CYCLE.
Larve may live as long as 279 days; they may engorge as soon as 3 days and in summer molt as soon as 8 days, a total effective temperature of 350° F. being required. Nymphs may live 476 days; they engorge as soon as 3 days and may molt 13 days after dropping. A total effective temperature of 657° F. appears to be necessary to produce this molt. Adults may engorge in 9 days, commence depos- iting 5 days later, and deposit as many as 8,330 eggs. The eggs hatch as soon as 23 days, requiring an effective temperature of 862° F. for incubation.
ECONOMIC IMPORTANCE.
This species is of considerable economic importance as an external parasite. It readily attaches to domestic animals and man. As its mouth parts are long and permit of deep penetration, the attachment of the tick causes considerable inflammation which frequently ends in suppuration. In Texas and Louisiana, where this species is abundant, cattle in particular suffer from heavy infestation. In the Eastern and Southern States man is more frequently attacked by this than any other species. Moss gatherers in Louisiana are greatly annoyed by its attacks (Morgan, 1899). At dairies milkers are an- noyed, particularly by the males which leave the cows and attach to them. This tick may attach in the ears and be the indirect cause of ‘‘sotch” in donkeys. Mr. J. D. Mitchell has observed that on hogs this tick attaches by preference to the belly, where even in the case of engorged ticks, the swelling of the skin is sufficient to almost hide them. Suppurating pustules were observed on this host where the ticks had dropped off. Attempts to transmit Texas fever by this tick have failed (Mayo, 1897; Morgan, 1899).
A correspondent in south-central Missouri reports that this tick is a serious pest to poultry there. The larve attack young chickens in such numbers as to kill them. He also states that the larve and adults are very annoying to man and domestic animals.
poetical,
THE CAYENNE TICK. 151
NATURAL CONTROL.
In order to determine the effect of water seven partially engorged females were submerged May 29, 1906, for 18 hours. After removal all became active and on May 30 were again submerged for 45 hours, ° only one surviving. As yet no parasites have been found to attack this tick. The natural enemies of the cattle tick, as described in Bulletin 72, undoubtedly destroy large numbers of this species.
ARTIFICIAL CONTROL.
Owing to the great longevity of the nymphs and adults, and to the many hosts which this species attacks, the rotation method of eradi- cation is impracticable. Frequent mopping or dipping with any of the standard tick dips must be resorted to. To be effective, mopping, dipping, or hand picking should be practiced often enough to destroy the females before they become engorged; that is, every 10 days.
THE CAYENNE TICK
Amblyomma cajennense (Fabricius). DESCRIPTIVE.
The common name of this species is taken from the locality in which it was first collected and from which the specific name was taken; that is, Cayenne, Guiana.
Adult (Pl. XII, figs. 2, 3, 5-7) —Males from 3 by 1.75 mm. to 4 by 2.50 mm. Females, unengorged, 3.5 by 2 mm. to 4.25 by 2.5 mm.; engorged, from 10 by 7 by 4 mm.to 12 by 8 by 6mm. Males pale yellow or brownish yellow, with irregular silvery white markings or streaks, and brown or reddish brown spots, all arranged to form a definite but complex pattern. Unengorged female yellowish; scutum largely silvery, with a brown line on each margin reaching back from the eyes. Engorged females dull bluish gray, with dark purplish brown reticulations.
Nymph (Pl. XII, fig. 4)—Unengorged, 2 by 1.25 mm.; engorged, from 3.25 by 2 mm. to 4 by 2.75 mm.; length of capitulum 0.407 mm. (from tip of palpi to base of emargination of scutum); scutum 0.561 mm. long by 0.786 mm. wide. Upon emerging the nymphs are of a dark-brown color; this soon turns to light brown, with intestinal markings showing through as dark-brown bands. As with amer- icanum, the sex of the nymph can be told a day or two prior to molting by the silvery markings which show through the to-be- molted skin.
Larva (Pl. XII, fig. 1) —Unengorged, 0.65 by 0.51 mm., yellow- ish, the scutum marked on the lateral margins with dark red; engorged, 2.5 by 2 mm., ovoid, bluish gray. Length of capitulum 0.195 mm. (from tip of palpi to base of emargination of scutum); scutum 0.248 mm. long by 0.374 mm. wide.
152 LIFE HISTORY OF NORTH AMERICAN TICKS.
Egg.—Ellipsoidal, deep yellowish brown, shining, smooth. The average size of 10 eggs measured was 0.487 by 0.431 mm.
HOST RELATIONSHIP.
The type host of this tick is not known. It attaches readily to a large number of mammals, having been taken in Texas by agents of the bureau from the horse, mule, ox, goat, coyote, peccary, and man. Other hosts recorded are dog, hog, capybara, anteater, and toad. Mr. A. H. Jennings has collected this tick in Panama on the dog, horse, ox, and deer (Qdocoileus toltecus). Mr. D. K. McMillan obtained one partially engorged female from a Mexican lion ( Felis hippolestes aztectus) at Raymondville, Tex. On November 20, 1907, a flock of 75 goats in the vicinity of Brownsville, Tex., was examined for ticks. Larve of this species were found in large numbers on the ears and over the eyes of all examined, while partially engorged nymphs were occasionally found. Adults were collected in this same locality, associated with Dermacentor nitens in the ears of horses. However, they appear to prefer the abdomen or between the legs as places of attachment. On April 22, 1908, Mr. H. P. Wood found horses and mules at Brownsville to be badly infested by this tick. Messrs. E. A. Schwarz and F. C. Bishopp found this species to be very annoying to man in the vicinity of Tampico, Mexico. Horses appeared to be the host most commonly attacked by the adults. Newstead observed this tick in Jamaica to occur more particularly on equines and less abundantly on cattle. This has been the same in our observations. Newstead states that there are authentic records of the occurrence of this tick on the tongues of young calves. As illustrating what a great pest this tick is to man, he states that 27 adults of both sexes and swarms of larve were taken from his body after passing through a small native settlement in Jamaica. Stoll (1886-1893) has described a similar habit in the tick in Mexico and
Central America. GEOGRAPHICAL DISTRIBUTION.
(Fig. 12.)
The type locality of this species is Guiana. It has been collected at several points in southern Texas by agents of the Bureau of Ento- mology, being particularly abundant at Brownsville. The Marx collection contains an unengorged female labeled as collected at Bis- cayne Bay, Fla. It seems quite probable that records of this species from Arizona are based upon a jar of ticks which are incorrectly labeled. Banks records having seen specimens from San Diego County, Cal. This is, with the possible exception of Margaropus annulatus australis, the most common species in Mexico and Central America. It has been reported from Mexico, Guatemala, Honduras, Nicaragua, Costa Rica, Panama, Bermuda, Cuba, Jamaica, Trinidad, Colombia, Venezuela, French Guiana, Brazil, Paraguay, and Argentina.
THE CAYENNE TICK, AMBLYOMMA CAJENNENSE, AND THE PACIFIC COAST TICK, DERMACENTOR OCCIDENTALIS.
Amblyomma cajennense: Fig. 1.—Unengorged larva. Fig. 2—Unengorged female. dorsal view. Fig. 3.—Male, dorsal view. Fig. 4.—Unengorged nymph (balsam mount). Fig. 5.—Male, ventral view. Fig. 6.—Unengorged female, ventral view. Fig. 7—Engorged female, dorsal view. Dermacentor occidentalis: Fig. 8.—Male, dorsal view. Fig. 9.—Male, ventral view. Fig. 10.—Unengorged female, dorsal view. Fig. 11.—Unengorged female, ventral view. Fig. 12.—Fully engorged female, dorsal view. (Original.)
ih rel mt » eo iw “any ied i es eS 4% * ‘ =< . je sad PT ¥ ‘, a ets. + B hg ¥ 5 55 We é > a> }- ? >.
THE CAYENNE TICK. 153
LIFE HISTORY. Observations on the biology of this species have been made by Hunter and Hooker (1907), Hooker (1909), Rohr (1909), and New- stead (1909).
Fig. 12.—The Cayenne tick, Amblyomma cajennense: Distribution in North and Central America. The large dots show localities where the species has been collected in our investigation. The small dots indicate the probable range of the species. (Original.)
The egg (Table LXVIT).—In the laboratory in August, at a mean temperature of 84° F., oviposition commenced on the ninth day fol- lowing dropping while out of doors, at a mean temperature of 84°F., 11 days passed. Eight of 10 females collected April 22, 1908, and kept in the laboratory at a mean temperature of 63° F. commenced
154 LIFE HISTORY OF NORTH AMERICAN TICKS.
oviposition on the eighteenth day, the other two beginning oviposi- tion on the sixteenth and twentieth days after collection. The average preoviposition period for 13 ticks was 16.5 days and the average oviposition period was 19.7 days. In the laboratory in May, at a mean temperature of 77° F. oviposition continued for as long as 23 days. The largest number of eggs recorded was 4,789, which were deposited in the laboratory in 20 days following May 10, 1908. The largest number of eggs deposited in 1 day was 447. The average number of eggs deposited, based upon records of 13 ticks, is 3,536. All of the females used in these counts were collected individuals and may not have been completely engorged. New- stead states that Worthly has found 7,240 eggs to be deposited by an individual of this species and Rohr records 7,742 from 1 specimen. The minimum incubation period in the laboratory at a mean temperature of 80° F. was 37 days. Out of doors, at a mean temperature of 78.5° F., 54 days passed before the eggs hatched. Under similar out-of-doors conditions, when the mean temperature was 66.2° F., the incubation period was 154 days. The effective temperature required for embryonic development appears to be 1,370°. Newstead reports that at an average temperature of 75° F. incubation was completed in from 43 to 50 days.
Taste LXVII.—Preoviposition, incubation, and larval longevity of Amblyomma
cajennense. Temperature during incu- bation. Date en- Mini te gorged Eggs de- | Hatching a ren Larval Sita posited. began. batign All larve dead. longevity. ese Total opped. period ° Maxi-| Mini-}] age afta mum. |mum.| daily tive mean j 1908. 1908. 1908. Days. 1909. Days. Sy de 10 wpe oo, Mar 25-2 |e pr4 ool sme sc. BO cacsapae ek ole es a ge ae Ak 90 47 | 74.15 | 1,745 Mary 30522|) Acpr. W522.) June Oe ek 56 | Apr. 22-May 7..... 317-332 | 90 47 | 74.36} 1,756 Apr. 2222-2), sumedi2. = 52 | Nov. 9-16,1908..... 150-157 | 90 47 | 74.66} 1,647 Apr: 24....=| Jume13).. - 51 | Apr. 16-May 7 91.5 47 | 74.89 | 1,627 May 8....- June 19... 43 | Jan. 13-22 91.5 63 | 78.57 | 1,520 May 13....} June 21.. 40 | June 8-16 91.5 65 | 78.89 | 1,436 May 15....| June 22... 39 | June 9-24 91.5 67 | 79.35 | 1,418 May 20....| Jume 26... 38 | Before June 25 91.5 68 | 80.04 | 1.408 May 22....| Jume 27... 37 | June 25-July 13 91.5 68 | 80.11 | 1,373 Aug. 26-28.| Oct. 9..... ABM AGE UOh ss seuss oiels 189 | 97.5 51 | 78.15} 1,581 1909. 1909. 1910. Aug. 29-30.| Oct. 21...- 54, || MebylO—2422 522 ee 112-136 | 97.5 51 | 76,75 | 1,823 May 18....| June 29... 43 | May 20-July 16.-..-- 325-382 | 100 47 | 90.53 | 1,897
The following are at outdoor temperature:
1908. 1908. 1908. 1909. Apr. 22...| May 9..--- Jiilyal aes aa sne SO ses yao eee 364 |} 91 63 | 79 1,944 IAT 22). | ea Oo22 oe July 152-2. Daath ys 4 eee 368 | 91 63 | 7 1,944 ADS 22-2 |e Mayigia =: June 30... 53 une do. see Bee eean 350 | 91 63 | 78.98 | 1,907 Apr. 22...| May 9..... June 30... beh a iplne dis oodase aes Se Spill Wil 63 | 78.98 | 1,907 Aspr.22.2.|) May 9.2522 June 30... FJ [aes 0) ail: ane a enya 288 | 91 63 | 78.98 | 1,907 1909. Aug. 17...| Aug. 28...| Jan. 28..-.. PSA Mar 126 eee 57 | 99 17 | 66.23 | 3,422
eee ee ee ee eee
- THE CAYENNE TICK. 155
The larve (Tables LXVII, LXVIIT).—The greatest longevity of larve observed by us was 386 days: These larve hatched June 24, 1908, and were kept in a tube on moist sand in the laboratory. As is shown in Table LXVII, the greatest longevity out of doors was 368 days.. In many cases we have observed a few larve to be alive over a year after the first eggs deposited by the parent had hatched. The minimum period required for engorgement was 3 days, the greatest number dropping on the fourth day. Newstead states that on man engorgement is completed in from 2 to 4 days.
TasLE LXVIII.—E£ngorgement of larve of Amblyomma cajennense on bovine.
Total
Date larvz applied. number ee eae eee TS | 7 | aia | es = wey oe: LOOT 2 P33) oP 0 0 20 63 9 0 0 0 0 0 92 PRG SO on a 0 0 0 56 40 3 0 0 0 0 99 Mn 24, 1908. RE 0 0 0 12 17 30 + 0 0 0 63 cy, i a 0 0 o| 2! 2 0 0 0 0 0 44 cig CSE |S ee ee eee 0 0 0 18 64 0 0 0 0 0 §2 LE ig 1 Aa ie ae ee ee 0 0 0} 185 77 20 0 0 0 0 282 Spee NG et, ee 0 0 0 0 8] 17 0 0 0 0 25
A few days after dropping the larve cluster together, as ln ameri- canum, and become quiescent. Soon the anterior part of the body becomes light colored, showing that metamorphosis is taking place. The shortest period in which molting took place was (at a mean tem- perature of 89.8° F.) 10 days. In this instance a total effective tem- perature of 468° F. was accumulated. All of the larvz observed were engorged on bovine animals except three lots which were engorged on guinea pigs.
The nymph (Table LXIX).—In order to determine the longevity of nymphs, 20 that molted July 29, 1907, were isolated in a tube. On November 13, 1907, all were alive; on March 15, 1908, 15 remained active; on July 12, 12 were alive, and on July 29, 8 were alive. On September 5, 1908, 5 were still alive, after a period of 1 year and 43 days. Another lot of 40 nymphs which molted from larve September 29 to October 5, 1908, contained 1 individual which lived until June 21, 1909, a period of 265 days. Ina third lot which became nymphs September 28, 1908, 5 specimens were alive after a period of 269 days.
The shortest period in which engorgement took place was 3 days, the largest number dropping on the fourth and fifth days.
156 LIFE HISTORY OF NORTH AMERICAN TICKS.
TaBLE LXIX.—Engorgement of nymphs of Amblyomma cajennense.
Nymphs dropped engorged—days following
application, Total Date nymphs applied. Host. number dropped LO EDs raat yas sre) |) Ona tdiag | reams nel nal Oe taal cd
AICS TO: VOD FEELS Osho Bovine eee: ORO) roe Sah Set On ON Or 0) | 0 13 OCU ONIG( Pu ire ee any eenell Liecae Ole cee 25) 10h) COMO On ES shi Qala ies le ON Ona O 22 July 25°a1908- As ae Sey ea a doses OPO EeZe LZ aha He 2ON On| aOeh) On OL 10 21 Tests ee See A Oe Co Ca ety OF Ob ete 2a On OAs Ou One 14 Milhived sal O09 8 eo = oan oe ee donsate4 = Oo SSOe SOF OFS Sr SOs ON Sen rOs|= 204) 20 8 ETSI Dee ene scenes lh eee dO ee OP SO Oe | OW Oy IIE OP ea Oar 38 ATI E226 F909 2a 2s ss SA | dotetss OF OR RON PEAS Fo 28) OR AO PAOFaeOn| Os} a0 6 DeCHID; AG09 ees ee ee oe (tGuineapigss—-|) Os On Oo Os cOn On Oo On OO n| eat 1 HED wo PIGIOR mers pee | (Boviness-o-s5- Os ON OR OF Sets 2a Os ON On EO haaO 3 APT 25 OU jatg2 Qui vila ale peael eg dopey ONS ONO) 4s OM ON SOR EsOs 10h) 080 4
In August, 1909, at a mean temperature of 89.5° F., molting com- menced as soon as the twelfth day from dropping. The longest time observed to be required for molting was 105 days. During this period the mean temperature was about 53° F. An effective tem- perature of 558° F. appears to be required for molting.
The adult (Table LX X).—Of 103 individuals, the sex of which was determined at the time of molting, 65, or 63 per cent, were females. The greatest longevity among adults observed by us was about 466 days. This was the record of a single female which, together with 5 males, was kept on moist sand in the laboratory. These specimens molted in September, 1907. The last male died about December 1, 1908, while the female lived until December 25 of that year. One of 6 females which molted May 20-26, 1908, lived between 381 and 392 days. In another instance a male and a female which became adult September 11-13, 1909, died between 340 and 380 days later. The longevity of 7 other lots of ticks observed during 1908-1910 ranged from 133 to 366 days. All were kept in the laboratory and were not fed as adults. The length of life of males and females appears to be about the same.
Mating, so far as known, takes place only on the host. When placed upon a host the males and females attach readily. In one case a female was observed to remain in the bag covering the scrotum 5 days before attaching. However, they usually attach within 24 hours. Several days, and frequently a week or more, of feeding appear to be required before the male goes in search of a mate. In our observations the males have remained mated for only 2 or 3 days, and often a shorter period, before leaving in search of other mates.
The shortest period in which a female engorged was 7 days and the longest 12 days. One male which was placed on the scrotum of a bull July 27, 1909, attached immediately. It was not observed to copulate with the females, but reattached several times. It was still attached on September 29, a period of 64 days after application and 41 days after the last female, put on the host at the same time, had dropped engorged. During the period while this male was attached
THE CAYENNE TICK. 157
a second lot of females was applied and had become engorged. When attached the entire length of the hypostome is buried in the flesh, the palpi bending back and touching the anterior part of the scutum.
TaBLE LXX.—Engorgement of females of Amblyomma cajennense on bovine.
Engorged females dropped—days
following attachment. Total Adults applied. Date of attachment. number dropped. 7 8 9 10 11 BE Dingo LOO ie se aoe eee ioe | ac eeninieere sic eae a= oc Meee Pod” 3 | OS (ete ape ss 2 Bisans9, W908 est cece st ash | sac Pokus c sels te eee ee ES Ra eer See Oe ase © eee 4 1 5 PLY O; LOUD aie whe ayosage wap JD See ae eee Be Pee Tas ieee i tt ees of 2 Tula Dil ONO Sz aeeest ek 3k AG) Rahal EW be be Se eed ee ee Uses aera eee 1 Ras ss: 2 DQpb. 13,0009. 2 -5..2o2st he SOpbs Wee tee se ee ee ee a alae sad eke os olla v et 2 1 3 Ob. .assacietttass SSeenc8 ola) ULE, 7 a eee eget Meee Us eke Ses St, Seeks esate ae 9 1 otal ss ce vs 25. 5 Peer eA chee Sees Scheer goles - 15 LIFE CYCLE.
Larve may live as long as 386 days. In summer they may en- gorge in 3 days and molt as soon as 10 days after dropping. A total effective temperature of 468° F. appears to be required for this trans- formation. Nymphs may live more than 134 months if they do not find a host; they engorge as soon as 3 days and molt as soon as 12. days after dropping. The nymphal molt requires an accumulation of 558° F. of effective temperature. Adults may live as long as 466 days if they do not find a host; they may engorge as soon as 7 days after attachment, commence ovipositing 9 days later, and deposit as many as 4,789 eggs. The eggs require 1,370° F. of effective tem- perature for incubation.
ECONOMIC IMPORTANCE.
In this country cajennense is of economic importance in the lower Rio Grande Valley of Texas only. In the vicinity of Brownsville it is very abundant at certain seasons of the year and is the source of great annoyance to horses, mules, cattle, and other domestic animals. Stoll (1890) states that in Guatemala the larve of this tick hang on the grass in clusters of thousands, and are the source of great annoyance to travelers. The collection of the Bureau of Entomology contains many specimens taken by Schwarz and Barber in Guatemala, upon their bodies. December 5-8, 1909, Schwarz and Bishopp found this species to be very abundant in all stages at Tam- pico, Mex. All stages were found in great abundance on horses, and in much smaller numbers on mules, donkeys, and cattle. The adults are especially bad pests to these animals. Many people stated that it was necessary to apply kerosene and lard to their horses at frequent intervals to lessen the number of ticks on them. While collecting insects in the vicinity of Tampico, these ticks proved very annoying. At times the trousers of Schwarz and Bishopp were covered with thousands of larve, many of which gained access to the skin and attached. Although much fewer in number, the bites of the nymphs
158 LIFE HISTORY OF NORTH AMERICAN TICKS.
and adults were much more troublesome. While the itching was intense, none of the points of attachment became infected and there- fore soon healed. In one case a nearly fully engorged larva was found under the knee, which certainly had not been attached more than 36 hours. Hunters and others who have occasion to spend consid- erable time in the forests complain a great deal of the attacks of this tick. Schwarz and Bishopp heard of one man whose legs were well covered with suppurating sores and who was ill from the attack of these ticks and the wounds produced by scratching. At Victoria, Tamaulipas, Mex., on December 9-10, a much smaller number of ticks were found; no larve were seen and horses were only lightly infested.
The Bureau of Entomology has received large numbers of males of this species from the Guinand Brothers of Caracas, Venezuela, with the statement that they are the source of great loss to the cattle- men in that country.
NATURAL CONTROL.
No observations of natural enemies of this species have been made by us. Newstead (1909) records the finding of engorged females in the stomachs of the tinkling grackle (Quascalus crassirostris). He also observed parrot-billed blackbirds picking ticks, probably of this species, from the heads of horses.
ARTIFICIAL CONTROL.
As with americanum the large number of hosts which this species has and the long periods which they can live without a host pro- hibit successful control by pasture rotation. Dipping, mopping, or handpicking must be resorted to when the species becomes a pest. Dipping as often as every 8 days would be required in order to prevent the dropping of engorged adults.
Genus DERMACENTOR Koch.
Five of the nine species of the genus Dermacentor which occur in the United States have been studied and are here considered. One species, Dermacentor venustus, has also been studied by Ricketts and by Cooley. This latter species is the only member of the genus that has been shown to transmit disease.
Two different types of life history were found to occur in the genus. While 4 of the species studied, namely, occidentalis, parumapertus var. marginatus, variabilis, and venustus drop to pass both molts off the host, nitens does not do so but transforms upon the host. Another species (Dermacentor albipictus) which is now being studied has also been found to have this habit. This habit of molting upon the host, as well as the preference shown by Dermacentor nitens for the inside of the ears as a place of attachment, where it is consider- ably protected from bird and other enemies and where it is not readily removed by the host, must be considered as protective adapta- tions. The adults of all species of this genus which we have studied
THE RABBIT DERMACENTOR. 159
excrete large amounts of what appears to be undigested blood,
while engorging. THE RABBIT DERMACENTOR.
Dermacentor parumapertus marginatus Banks.
The common name of this tick is taken from the fact that in the adult stage it is found on no other host than the rabbit, while the adults of other species of the genus Dermacentor are very rarely found on that host.
DESCRIPTIVE.
Adult (Pl. XIII, figs. 3-5).—Males from 2.5 by 1.25 mm. to 3 by 1.75 mm. Females, unengorged, 2.5 by 1.5 mm. to 3.75 by 2 mm.; engorged, 10 by 7 by 3.5 mm. to 15.4 by 10.7 by 7.7mm. The males have interrupted white markings along the lateral borders of the dorsum. The posterior border of the scutum of the females is white, the lateral borders with interrupted white markings. In both sexes the outer surface at the apex of the leg segments is marked with white, in which are usually two dark red punctations. Some specimens from California, Oregon, and Utah have no white visible, while others are nearly as strongly marked as those from New Mexico and Texas.
Nymph (Pl. XIU, fig. 2)—Unengorged, about 1.23 by 0.79 mm.; engorged, 3 by 2.1 by 1.2 mm. to 3.9 by 2.8 by 1.6 mm. Color, unengorged, reddish brown; engorged, dark slate to almost black. Capitulum 0.305 mm. long (from tip of palpi to base of emargination of scutum); scutum 0.524 mm. long by 0.521 mm. wide.
Larva (Pl. XIII, fig. 1)—Unengorged, about 0.686 by 0.433 mm. (alcoholic) ; engorged, 1.3 by 0.8 by 0.7 mm. to 1.5 by 0.9 by 0.8 mm. Color, unengorged, reddish yellow; engorged, dark slate. Capitulum 0.148 mm. long (from tip of palpi to base of emargination of scutum); scutum 0.260 mm. long by 0.344 mm. wide.
Egg.—Ellipsoidal, yellowish brown, shining, smooth. The average size of 10 measured was 0.65 by 0.47 mm.
HOST RELATIONSHIP.
The host of the type variety is the jack rabbit. The types of the species (D. parumapertus) are labeled as taken from man and in a chicken house. Nospecimens of this variety have been taken on other hosts than jack rabbit and cottontail rabbit. While very few larve and nymphs have been collected on rabbits, it would appear from the fact that no specimens have been taken on any other animal that the rabbit is the principal host of those stages. We have en- gorged larve in our rearing experiments on the fox squirrel, guinea pig, and bovine, as well as rabbit, and nymphs have been engorged on the guinea pig and rabbit.
Although a large number of unengorged adults have been col- lected, very few fully engorged females have been obtained. It would seem that a large number of them are scratched off by the host before becoming replete. The species is found principally in the ears of
160 LIFE HISTORY OF NORTH AMERICAN TICKS.
the host, but it also attaches on the outside of the ears, on the head, on the neck, and sometimes between the toes. Adults collected on rabbits have been found to attach readily to bovine hosts and to engorge to repletion. :
Fig. 13.—The rabbit Dermacentor, Dermacentor parumapertus marginatus: Distribution. The large dots show localities where the species has been collected in our investigation. The small dots indicate the probable range of the species in the United States. (Original.)
GEOGRAPHICAL DISTRIBUTION. (Fig. 13.)
Mesa City, Arizona, is the type locality for this variety. The species is confined to the semiarid and arid west, including Texas west of about the 101st meridian, New Mexico, Arizona, southern Utah, Nevada, California, and southeastern Oregon. It appears to
Bul. 106, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE XIll.
CoD
, =
THE RABBIT DERMACENTOR, DERMACENTOR PARUMAPERTUS MARGINATUS, AND THE TROPICAL HORSE TICK, DERMACENTOR NITENS.
Dermacentor parumapertus marginatts: Fig. 1—Unengorged larva. Fig. 2.—Unengorged nymph (balsam mount). Fig. 3.—‘‘ Deposited-out’’ female, dorsal view. Fig. 4.—Male, dorsal view. Fig. 5—Unengorged female, dorsal view. Dermacentor nitens: Fig. 6—Unen- gorged larva. Fig. 7—Unengorged nymph (balsam mount). Fig. 8.—Engorged female, dorsal view. Fig. 9. —Male, dorsal view. Fig. 10.—Unengorged female, dorsal view. Fig. 11.—Engorged nymph, ventral view. Fig. 12.—Engorged nymph, dorsal view. Fig. 13.— Engorged female, ventral view. Fig. 14.—Male (balsam mount). (Original.)
THE RABBIT DERMACENTOR. 161
be most abundant in western Texas and in New Mexico. Larve and nymphs have also been taken at Monclova, Mex.
LIFE HISTORY.
No observations on the biology of this species have been previously published.
The egg (Table LXXI).—In July at a mean temperature of 85° F. oviposition commenced as soon as the fifth day after dropping. Four of 7 ticks which dropped engorged during July and early August com- menced oviposition on the fifth day, the three remaining ones com- mencing a day later. The average oviposition period of 7 females observed in July and August was 15.9 days. The minimum oviposi- tion period was 11 days, within which time 855 eggs were deposited; the maximum, 26 days, during which period 3,247 eggs were laid. The maximum number of eggs recorded for the species is 4,660. The female which made this record deposited 918 eggs during one day. The females died in from 1 to 6 days after deposition was completed. One of the 7 engorged females upon which these counts of eggs were made was collected on a rabbit, while the other 6 females were engorged upon bovines. The measurements of the 6 were as follows: 10 by 7 by 4 mm., 12.5 by 9 by 6.5 mm., 12 by 8.5 by 6 mm., 11 by 7.5 by 4mm., 10 by 7 by 5mm., and 10 by 7 by 3.5 mm., respectively.
The shortest incubation period was 20 days, the mean tempera- ture during this period being 85° to 86° F. A total effective tempera- ture of at least 850° F. appears to be required for embryonic development.
TaBLE LXXI.—Jncubation and larval longevity of Dermacentor parumapertus margin- atus.
Temperature during incubation.
|
: Minimum Larval |
Eggs de Hatching be- | - All larve ‘ a gan. ats -g dead. longev- | | arins. | Average | otal period. ity. | Maxi- | Mini- daily | effective | mum | mum mean. oe
Days. | Days. te I. °F, "k June 30,1908 | July 23,1908 Ye Ee Seat Tes. aE Poe eee 95 70.0 81.1 954. 25 July 2,1908 | July 24,1908 ft RSA 8 ER te 95! 70.0 83.1 959. 75 July 18,1908 | Aug. 8,1908 22 | Jan. 25,1909 170 99 76.5 85.5 935. 75 July 20,1908 | Aug. 10,1908 22 | Nov. 30,1908 102 99 73.0 85.4 916.75 July 22,1908 | Aug. 12,1908 22 | Mar. 6,1909 223 99} 73.0 85.7 922. 75 July 24,1908 | Aug. 14,1908 22 | Mar. 12,1909 7 99 73.0 85.9 944.75 July 26,1908 j.....do....... 20 | Feb. 10,1909 197 99 73.0 86.2 863.75 July 27,1908 | Aug. 16,1908 21 | Oct. 26,1908 71 99 73.0 86.3 909. 00 July 28,1908 | Aug. 17,1908 21 | Feb. 15,1909 7 99 73.0 86. 4 911. 50 July 30,1908 | Aug. 19,1908 21 | Mar. 12,1909 222 99 73.0 86. 7 917.25 Aug. 3,1908 | Aug. 22,1908 Dec. 6,1908 106 99 73.0 86. 2 | 863. 50 Aug. 5,1908 | Aug. 24,1908 20 | Mar. 9,1909 214 99 73.0 85.1 857.25 Aug. 8,1908 | Aug. 28,1908 21 | Feb. 17,1909 167 96 73.0 - Bs S878. 25 Aug. 14,1908 | Sept. 4,1908 22| Feb. 5,1909 96] 75.0 4 908. 50 Aug. 16,1909 | Sept. 8, 1909 24 rae ss 193-221 110 77.0 89.38 | 1,112.75 ,191
Aug. 14,1909 | Sept. 3,1909 21 | Nov. 18,1909-| 76-144 110 77.0 89.51 | 976. 25
Jan. 25, 1910
The larva (Tables LXXI-LXXIII).—The greatest longevity of larve observed by us was 227 days. Engorgement has taken place as soon asthe fourthday. Asisshown in the last record in Table LXXII,
21448°—Bull. 106—12——11
162 LIFE HISTORY OF NORTH AMERICAN TICKS.
the longest period of engorgement observed was 14 days. In this case the larve were scratched off when between one-fourth and five- sixths engorged. Six of the 8 were engorged sufficiently to molt. The first lot recorded in the table did not attach readily and for this reason those ticks which did not take hold at first were allowed to remain in the bag. Thus the larve which dropped on the ninth day probably did not attach until the third day after application. In the third lot recorded in the table the squirrel escaped from the cage on the afternoon of the fifth day after the ticks were applied and was not put back until the next morning. There is little doubt that some larve dropped in the meantime.
TaBLE LXXII.—Engorgement of larve of Dermacentor parumapertus marginatus.
Larve dropped ongorbed dave following appli-
cation. Total Date larvee applied. Host. peeeacrl Bley] Bah SalyG 2) 71 Soil 8 Shoal ia Eee PR Sif L908 Fw ooo Sis cetsyemte Ceo Bovinesen ee =e OUR Ore Oe) eal ers i mies ene |) 13 ANI 626 5 1908S Ss Sc ae sec ee eee lowe « dose es aks ON eOn EOF ON aie 2a OF POR sO oO ian0) 9 OCU Oe1909F a eee een ees Squirrel. ...... OF Oe On ona cone On anO mins a0 23 INO V4 5 1G0O Soe eeee oe acee Guinea pig. - OO SON SON eZ eee ER Sa ie: Pee enOlieaG: 20 Marth 1910 82 es ee eae eed dOzeen- 282 OF Os) JON) On On a One 2a Ont 2250) 6 Dept..28, LOLOL SS susaatceeose|cecies doses ONT ONO O70) | On On One AOR tao riers 8
At a mean temperature of 87° F. molting occurred on the eighth day, an effective temperature of 350° F. having accumulated.
TaBLeE LX XIII.— Molting of engorged larve of Dermacentor parumapertus marginatus.
Temperature from drop- Engorged larve molted—days following dropping. . | ping to date iS first tick Date =| molted. en- i 2 orge lary ms Host 5 fe ro Pe) (eee is pe = 5 Eig | a4 2 | 8 | 9 |10/11}12)13] 14] 15/16] 19 | 20) 21 | 23} 24} 26| 39) 47] g Ey 3 cae 2 ae g a S| Ss 7 fe R q 3 ol Sia ie A Hla le i[< 1908. Seg as ace Aug. 12 | Bovine...... 1 O.- OF O| OO} TO} OF OF 0} OF CO}, 0} 0} 0} Oh. (0) Ol 96 7G S506 AAG AS I eas Ol cae 2 17 1) ONO} 0}. 10}, 40), 70)~ OC) 250) SO}, 0) 0) OOO Ole 296 ni 77a Some Ae 4a) sere Gon sacte 5 0} Oo} 2 3] OF OF OF OF OF OF CF OF OF OF OF OF O| 5/96 {76.5)/85.3 MATTE Sal) | eaeee dov= es 3 Oo; Oo}; 3} OF OF OF OF OF OF OF OF OF OF OF OF OF OF 3/96 {76 [84.8 AMIS UG Ile Fase Co oars 1 0} OQ} 0} A} 0} 0} 0}. 0} 0)" 0! 70} Ol 0} OO) 0) OSG 7G Stee INTE WA ee @Osasete 2+) 0} 2 Others missing. 0} 2)97.5/75 _ 185.0 1909. Oct. 13 | Squirrel. .... 12 0} 0} oO} OF OF OF OF 4) 8] OF OF OF OF OF OF OF OF 12/87 {51 167.83 Octe 14ae eee. Oecenss 5) 0} 0} OF OF; OF 61) A 2) 62) 0) 0}. OF O} 60} Ol) OF OO} 58% abt eae Oct dant ee. does. 5 oO} Oo} OF OF 1) Of OF 2 1) O OF OF OF OF OF OF OF 4/87 [51 {70.92 OctsiGiateas dowae ks 2 0} of O| OF OF OF OF OF} OF :CO| Ij OF OF OF OF O OF 1186 [51 170.93 Nov 3 Guinea pig. .| 2 oO} OF OF OF OF OF A} OF OF} OF OF OF OF 1) OF OF OF 1179 |41 |64.95 Nov.10 |..-... dos 2-252 2 0} oO} OF OF OF OF OF OF OF OF OF OF EOF 1) OF OF OF 1/79 |41 (64.75 Nov. i ~waee @Osocces 5 0} 0} OF O| OF} OF OF OF OF OF OF OF OF J 3] OF OF 579 |34.5)63.55 Novell2i|P ss do: 2-252 7 0} O} O| O} OF OF OF OF OF OF OF O| OF OF OF OF 2 279 |20 [54.45 INOVelSa|senee doorcce: 2 0} Oo} OF O| OF OF OF OF OF : OF OF OF OF 1] OF LY OF 279 [82 [61.35 1910. Marsiuialasees GOs Soee 2 joaqogaga og afo hy oO lO} OF OO OF OF 192 53 68. 54 Mar: 19)| 2s dove: -% 2 o| of OF OF Of OF OF OF O| 1] OF OF 1) OF OF O} OF 2/92 [53 71.82 Oct. 1212" GOes os 8 OF YO) 50) SO SOO Oyen 0 0 0} 6 0 0} O| 7/94 |43.5)/71. 58 Rotals\68--|e2elessleeeleoel Pee leee Palomo Meare ce S\leaeal\se ae[eeees
THE RABBIT DERMACENTOR. 163
The nymph (Table LXXIV).—The greatest longevity of nymphs observed by us was 175 days. This record was made on a lot of 7 nymphs which molted from larve October 27-31, 1910, and were kept on moist sand in the laboratory. In another lot of 22 nymphs which molted from larve October 27 to November 5, 1909, 2 were alive March 9, 1910, when they were put on a host, thus having lived at least 144 days. Three lots of unengorged or slightly engorged nymphs collected on rabbits lived from 30 to 100 days.
Attempts to get nymphs to attach to a bovine failed and in our early experiments no attachments were secured when the nymphs were put on tame rabbits and guinea pigs. In 1910, two attempts to attach nymphs to a fox squirrel failed, and similar results were experienced in two of six tests on guinea pigs. In one instance a single nymph attached readily to a guinea pig, and 2 nymphs put on a rabbit attached and engorged readily.
The shortest period of engorgement observed was 4 days and the longest 25 days.
TaBLE LXXIV.—Zngorgement of nymphs of Dermacentor parumapertus marginatus.
Nymphs dropped engorged—days following N application. | Total Date nymphs applied. Host. as number dropped. 4 8 9 10 12 19 25 |
Dec, 10, 1909 23220-6125 22 5. Guinea pig. . 9 0 1 0 1 1 1 0 4 a Eee | tea dol 325; 1 0 0 0 0 0 0 1 | 1 May 25, W010... .2... 202322255. Rabbit... ... 2 1 0 1 0 0 0 0 2
Nymphs which dropped in August molted in 21 days when the mean temperature was 88.25° F. One nymph which dropped Decem- ber 19, 1909, molted 123 days later. This was the longest molting period observed. During this period the mean temperature was 60.24° F. The mean temperature has a decided effect on the length of the molting period. The molting periods of those nymphs which become males and those which become females are about the same. A total effective temperature of 641° F. appears to be required to pro- duce this molt.
The adult (Table LX XV).—The number of individuals of each sex was practically the same in the adults which we observed to molt from nymphs. The greatest longevity recorded occurred in a lot of 11 males and 4 females which were collected on rabbits on April 21-25, 1910. On August 18, 1910, a male and afemale were alive, but these died before September 26, 1910, having lived between 115 and 158 days. Of a lot containing 21 males and 8 females which molted between May 12 and May 30, 1910, 2 males and 2 females lived between 80 and 137 days. A number of other lots of collected indi- viduals lived from 25 to 72 days. The longevity of the sexes is prac- tically the same.
Unengorged or slightly engorged males and females taken from rabbits have readily attached when placed upon a bovine host.
164 LIFE HISTORY OF NORTH AMERICAN TICKS.
They have been found to mate within a day or two and to continue in this relation for a number of days or until the femalesdropped. As many as three-fourths of the individuals collected in western Texas were found paired. In one instance a male was found paired with a female of Dermacentor variabilis. After the dropping of the female with which it had mated, one male was observed mated with a female of M. annulatus. It remained: 3 in this relation until it was removed from the host a week later.
About 30 lots of this species have been collected by agents of the bureau. In only two instances were any engorged females found. Engorgement of females that were removed from rabbits took place upon bovine hosts in 12 days. A female which was placed upon a tame rabbit with a male on May 25, 1910, did not show any sign of engorging until 10 days later, when it was observed in copulation. Engorgement began on the third day following mating, but the date of dropping of this individual was not recorded. The females, during engorgement, excrete large quantities of material which when dry resembles coagulated blood. This frequently incrusts the male which is beneath the female, thus rendering him helpless and sometimes actually killing him.
The ear of the rabbit, both inside and outside, appears to be pre- ferred as a place for attachment. The large number of males that have been taken from rabbits is sufficient evidence that they remain upon the host for a long period after the females have dropped.
TaBLE LXXV.—Engorgement of females of Dermacentor parumapertus marginatus.
| Females Sa Adults applied. Host. | dropped Period of attach- Size engorged. engorged. Days. AUINOS LOOSE. ote eee eee ee Bovine....}| June 21, 1908 13 | 10 by 7 by 4mm. dene} 29; 1908 2/8. << 2. se2cee Se Seg ace dors: 2 July 11,1908 12 | 11 by 8.5 by 5mm 1D Yo) Spin i tears ll on ce ie E78 8S do....| July 14,1908 15 | 12.5 by 9 by 6.5 mm Frey a7 WOOS wn et prs See a ape oseare July 19,1908 12 | 12 by 8.5 by 6mm 1D 0 SE palin eat igh eee oie HOO Samer July 21,1908 14} 11 by 7.5 by 4mm 1D ere os See a See eee ie asa dows - July 25,1908 18 | 10 by 7 by 5mm. WO ee esos ea eee ae eee does 2.5 Aug. 2,1908 26 | 10 by 7 by 3.5 mm. Aug. 27, 1908...... ws. Be | ser S is doi <8 Sept. 5,1908 | (Sloughed off.) 9 | 10 by 7 by 4.5mm. June 25, 1909). 5 3s 22. eee ee See coe AMON ses July 7,1909 12 i LIFE CYCLE.
Larve may live as long as 227 days; they engorge as soon as 4 days after application and may molt in 8 days after dropping, a total effective temperature of 350° IF. being required.
Nymphs may live as long as 175 days; they may engorge in 4 days after application and molt as soon as 21 days after dropping, a total effective temperature of 641° F. being required.
Adults have been found to live for more than 115 days. Mating takes place on the host. Females may engorge as soon as 12 days after being put on a host; they may begin oviposition as soon as 5 days after dropping and deposit as many as 4,660 eggs. Deposition may continue for 26 days. Embryonic development may be com-
Bul. 106, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE XIV.
,
Fig. 1.—‘‘ Deposited-out’’ female with eggs. Fig. 2—Unengorged larva. Fig. 3.—‘‘ Deposited-out’ female, frontal view. Fig. 4.—Engorged larva. Fig. 5.—Engorged female, dorsal view. Fig. 6.— Unengorged female, dorsal view. Fig. 7.—Male, dorsal view. Fig. 8.—Male, ventral view. Fig. 9.—Unengorged female, ventral view. (Original.)
THE ROCKY MOUNTAIN SPOTTED-FEVER TICK. 165
pleted in 20 days, a total effective temperature of 850° F. or more being required. - ECONOMIC IMPORTANCE. This variety of Dermacentor paruma pertus has not been taken on any other host than the rabbit; hence it is of no importance economically.
NATURAL CONTROL.
Rabbits kept in cages have been observed to scratch off and devour fully engorged females. It seems probable therefore that some of these ticks suffer the same fate in nature.
To test the effect of heat upon eggs of this species, a bunch of freshly deposited eggs was placed on the ground in the sun from 3.55 p.m.untilsunset. When the eggs were put out the atmospheric tem- perature was 110° F. and the soil surface temperature was 133° F. The eggs were somewhat shriveled when taken in and later they dried up completely. They showed no sign of embryonic development, while acheck lothatched in9days. There islittledoubt that heat and dryness are important in controlling the abundance of this species.
One of two nymphs collected on a rabbit at Green Valley, Cal., on June 11,1909, was found to be parasitized by Hunterellus hookeri. This is the same species which acts as a parasite of the nymphs of Rhipicephalus sanguineus.
THE ROCKY MOUNTAIN SPOTTED-FEVER TICK.
Dermacentor venustus Banks.
The common name of this species is taken from the fact that it is the transmitter of the disease of man known as Rocky Mountain spotted fever.
DESCRIPTIVE.
Adult (Pl. XIV, figs. 1, 3, 5-9) —Males from 2.1 by 1.5 mm. to 6by3.7by14mm. Females, unengorged, from 3.1 by 1.8 mm. to 5.1 by 3 mm.; engorged, from 13.8 by 10 by 6.4 mm. to 16.5 by 11.4 by 6.9 mm. Male reddish brown; scutum with an extensive pattern of white lines; usually but little white on the middle posterior region; legs slightly lighter than scutum; joints tipped with white; female with scutum mostly covered with white; abdomen reddish brown; legs as in the male.
Nymph. —Unengorged, from 1.36 by 0.72 mm. to 1.54 by 0.8 mm.; engorged, from 3 by 2.1 by 1.3 mm. to 4.8 by 3.3 by 2 mm. Color, unengorged, reddish brown; engorged, dark bluish gray. Capitulum 0.336 mm. long (from tip of palpi to base of emargination of scutum) ; scutum 0.550 mm. long by 0.554 mm. wide.
Larva (Pl. XIV, figs. 2, 4) —Unengorged, from 0.631 by 0.387 mm. to 0.703 by 0.445 mm.; engorged, from 1.28 by 0.76 mm. to 1.43 by 0.85 mm. Color, unengorged, yellowish brown; scutum darker to- ward posterior end; engorged, slate-blue. Capitulum 0.139 mm.
166 LIFE HISTORY OF NORTH AMERICAN TICKS.
long (from tip of palpi to base of emargination of scutum); scutum 0.241 mm. long by 0.350 mm. wide.
Egg.—The average size of 10 eggs measured was 0.645 by 0.460 mm.; light brown, shining, smooth.
HOST RELATIONSHIP.
The host of the type of this species is not known. Most of the infor- mation herein presented regarding the host relationship of the species was obtained in the Bitter Root Valley of Montana. The work there was conducted under the general supervision of Mr. W. D. Hunter, but under the immediate direction of Prof. R. A. Cooley. Mr. W. V. King, of the Bureau of Entomology, and Mr. C. Birdseye, of the Bureau of Biological Survey, spent the spring and summer, and Mr. A. H. Howell, of the Biological Survey, a portion of the spring of 1910 in the center of the area where Rocky Mountain spotted fever occurs in its most virulent form. Messrs. King and Birdseye continued this investigation throughout 1911 in the same locality. To these men, who exposed themselves to the dangers of infection in order to collect information regarding this tick and its hosts, we are greatly indebted. In order to identify with certainty the species of ticks collected, the immature stages were sent to the laboratory at Dallas, Tex., and reared to adult and determined. It has been found that practically all of the small mammals act as hosts for the larvee and nymphs, while the adult stages are seldom found on other than the large domestic animals. Horses and cattle appear to be by far the preferred hosts. Among other domestic animals upon which adults have been found are sheep, mule, ass, dog, hog, goat, and cat (probably unattached). The principal wild mammals found to act as hosts for this stage are the mountain goat, brown bear, coyote, woodchuck, rabbit, wild cat, and badger. .The last three appear to be rarely attacked by the adults of this species. The immature stages have been taken on the following hosts which are arranged approxi- mately according to their relative importance: Ground squirrel ( Citel- lus columbianus), pine squirrel (Sciurus hudsonicus richardsont) , chip- munks (Futamias lutewentris, Eutamias quadrivittatus umbrinus), rock squirrel (Callospermophilus lateralis cinerascens), woodchuck ( Marmota flaviventer), rabbits (Sylvilagus nuttalla and Lepus bairdi), wood rat ( Neotoma cinerea), gray meadow mouse ( Mcrotus nanus canescens), pika (Ochotona princeps), white-footed mouse (Peromyscus maniculatus artemisiz), large meadow mouse (Microtus modestus), jumping mouse (Zapus princeps), and pocket gopher (Thomomys fuscus).
Dr. H. T. Ricketts and Prof. R. A. Cooley have given a consider- able amount of information on the host relationship of this species. Dr. Ricketts states that in Idaho this tick was found on the snow- shoe rabbit (Lepus bairdi) in considerable numbers in all stages of
THE ROCKY MOUNTAIN SPOTTED-FEVER TICK. 167
development. It seems very probable, in the light of our recent investigation, that this note applies to the rabbit tick, Hamaphysalis leporis-palustris. Additional information on the host relationships of this species is given by Hunter and Bishopp (1911b).
Fig. 14.—The Rocky Mountain spotted-fever tick, Dermacentor venustus: Distribution in the United States. The large dots show localities where the species has been collected in our irtvestigation. The small dots indicate the probable range of the tick. (Original.)
We have been able to engorge all the stages of the Rocky Mountain spotted-fever tick on the guinea pig, tame rabbit, and bovine, and the adults have been engorged on the goat.
168 LIFE HISTORY OF NORTH AMERICAN TICKS.
GEOGRAPHICAL DISTRIBUTION. (Fig. 14.)
The type locality of this species is Soldier, Idaho. The distribu- tion of this tick has been rather accurately determined by the Bureau of Entomology working in cooperation with Prof. R. A. Cooley and numerous correspondents throughout the Western States. The tick has been found to occur from British Columbia southward to north- ern New Mexico and from the foothills of the Rocky Mountains in Colorado to the base of the Cascade Range in Oregon and California. It is very abundant in western Montana, and throughout Idaho, east- ern Washington, and Oregon, northern Utah, western Wyoming, and northwestern Colorado. A detailed statement regarding the distri- bution of this species has been published (Bishopp, 1911a).
LIFE HISTORY.
Observations on the biology of this tick have been published by Ricketts (1906, 1907, 1908) and by Cooley (1909, 1911).
The egg (Table LX XVI). —The preoviposition period of this species varies from 5 to 17 days. One partially engorged female which was picked from a host March 24, 1910, had a preoviposition period of 25 days. The temperature experienced by these ticks can not be given accurately, as the ticks were collected in Montana and mailed to the laboratory at Dallas. Females which dropped from hosts at the Dal- las laboratory showed a variation of from 6 to 14 days in their pre- oviposition periods. The shorter period was recorded on specimens kept at 66° F. and the longer on specimens kept at 79° F. However, preoviposition periods of 7 days were observed when the mean tem- perature was about 80° F. and when the mean temperature was 68° F. preoviposition periods as long as 14 days were observed. The period of deposition varied from 15 to 32 days. The maximum number of eggs deposited by a female was 7,396; the average of 11 was 5,421.8. The individual which deposited the maximum number of eggs measured 16 by 11.5 by 6.1 mm. before deposition was begun. The number of eggs deposited by an individual is governed largely by its size.
Females which were removed from a host when about one-fourth engorged have been found to deposit fertileeggs. Three females which measured 8 by 5.5 by 2 mm., 8.3 by 5.3 by 2 mm., and 8.5 by 5.5 by 2 mm., began depositing on the fourteenth, tenth, and twelfth days after being removed from the host and deposited 211, 1,019, and 636 egos, respectively.
The minimum incubation period recorded was 16 days. This occur- red in the case of eggs deposited June 13, 1908, which experienced a mean temperature of 81.4° F. <A total effective temperature of 614.75° F. was accumulated during this period. Ricketts states (1909a, p. 100) that in Montana eggs deposited in July hatch in from
THE ROCKY MOUNTAIN SPOTTED-FEVER TICK. 169
30 to 50 days after they are deposited. Records made by Mr. W. V. King show the incubation period to vary from 34 to 51 days in the Bitter Root Valley in Montana.
TaBLE LXXVI.—Preoviposition, incubation, and larval longevity of Dermacentor
venustus. | Temperature during incuba- Pre- | Mini- tion. peak d ovi- | mum Larval “entie | Deposition | posi-| Hatching |incu-| All larvee | “4, emale ; : on j | T d d began. tion began. ba- dead. avit _ j|Aver otal ropped. peri- tion S°V"'Y-) Maxi-| Mini-| age |effective od. peri- mum, | mum. | daily | temper- od. mean.) ature. Tl Sate ESS Oy ee eee Ps Pace) Ses fe Sells 1908. 1908. Days 1908. Days. | RE he Oe OB ll aie June 6.. June 24.......- 7 eee Ae 91.5 69 |80.8 | 718.25 WHE 72 sete sl ao a52 aoe dqscts. Me See ae ee 91.5 69 |80.8 680.5 Fune 13.....-|-.....| June 28.......- TG) SURE y gees RS 91.5| 71 (81.4 | 614.75 i Sy SB VARS be "| ee me) Pete coe eceeass 90 71 80.8 641.75 1909. 1909. 1909. 1July 1| Before July Is") daly 31.2... .525 18+ — Sept. lg Ses, a Be | nee a ee 14. s 1 Junell | June 27...... 16:| July 452.22"22- 19 Aug, 26-Sept. 42-62 | 102 47 \91.8 917 1910. 1910. 1910. are 28) ADT Teo. cess 10) May Ge 2s 34 July 19-Aug. | 70-87] 91 43 |70.49 | 744.66 5.
Lr cee fal (REG ge 10" Mayriot 2a: 33 ci ee July 61-| 95 51 |74.6 979.6 Apr, 12) Apr. 18.....- Gilece sa MO ee. oe 32 inby. 19-Aug. | 61-78 | 91 43 |70.33 74. 56 De. ..t) Ape. 2s. 10 |) ‘May 25:.:.-... 34 ae eee cee 75 | 91 43 74.8 |1,081.2 -1Apr. 13 oe. | ia es qyere . 5 36 Aug. 5-20....| 72-87] 91 43 |71.78 |1, 036. 08 Apr. 26] May 2....... 6| May 31........ 30 uly 20-Aug. | 50-66 | 91 59 |71.66 | 859.8 1May 1] May 10...... 9 | June 6.... 28 way, 21-Aug. | 45-60 | 100 59 |77.02 | 952.56 1 May 14| May 23...... Ou MUNG Oe se. BE he: 25-31....| 74-80 | 100 60 |79.64 | 769.44 1June 4] June 13...... 9°) June 29: 20.5. h Lf Sept. 29... -...< 92] 97 69 |84.37 | 703.29 Ges HOw ess. oy ae ol ge eae eee 19 Aug. 25-31...) 55-61 | 97 69 (84.59 | 790.21 July 16 | July 25...:.. 9| Befowe Aug. | 17— | Sept. 24-Oct. | 45-56 | 104 79 |90. 19 | 755.23
10. 5. 1911. 1911. 1911. | Mor.) 20 Apr. 4...25-- hile Magy Ts 292s 41 | Ce Pe clyde 89 §2 (71.7 |1,1%6.7 }
1 This tick was picked from the host.
The larva (Tables LXXVI-LXXVIII).—The longest time between the beginning of hatching of a lot of eggs deposited by a single female and the death of the last larva was 92 days. In this case the eggs and larve were kept on moist sand in a tube in the laboratory. Hatching began on June 29, 1910, and the last larva died on Septem- ber 29. In the majority of cases in a series of over 200 observations the last larva died within 85 days from the time the first eggs in the lot hatched. In a number of lots of eggs separated from the parent female the day they were deposited the larvee all died within 2 months after hatching, even though kept under the most favorable conditions. In a number of instances larve which hatched the latter part of July and early in August all died within a month. Cooley’s experiments in Montana (1909, p. 102), as well as tests made by we ¥i King in that State, indicate that the longevity of larve in Montana is about the same as that observ ed by us at Dallas, Tex.
On account of the fact that the period of deposition is frequently longer than the incubation period, in warm weather the larve begin
170 LIFE HISTORY OF NORTH AMERICAN TICKS,
to hatch from the first eggs deposited some time before deposition is complete.
Ordinarily larve attach within a very short time after they are applied to a host. However, we have observed them to remain unattached for three days when kept in close proximity to a host. The majority of the larve attach around the head and ears of the hosts. They are, however, frequently found on the back, especially between the shoulders. Larve when removed from a host when shghtly engorged were found to attach to another host several days or even weeks later.
In a number of instances larve which had awaited a host for two months were found to attach when placed on a host, but many, and in some eases all, died without engorging owing to their weakened condition.
The shortest period required for the engorgement of larve was two days. The greatest number drop from the host on the third, fourth, and fifth days after attachment. In two cases larve remained on the host for 8 days.
TaBLE LXXVII.—Engorgement of larve of Dermacentor venustus.
Larve dropped engorged—days following appli- cation.
Date larve applied. Host. thee banshee ae tye Ree meee
March s0lce cee ee esac ee Bovine. .2.---- 0 0 0 1 2 0 0 0 3 PERO: Eee S ahs ee. ee dOzsse-5 ces 0 0 23 27 17 13 3 1 84 MiaVelS Secccec nase ccee acer eres (OOkevcoaese 0 0 0 15 10 0 0 0 25 DU 85 oe Se was Oe ace eas dois. 2.826 0 0 2 3 0 0 0 0 5 Uy Ree Po ee sete once al eee COM eceets 0 0 76 64 12 4 0 0 156 1909.
Duly 28 UN a ees es eee Guinea pig.... 0 0 0 0 6 2 2 0 10 Pub y SO ess 2 eS ee Ru AMONG saan 0 0 0 0 6 5 0 0 11 DOM es Soe See eee Bovine........ 0 0 0 2 1 0 0 0 3 IAT END Sh 5 ee SE Rabbitss.2 2-2. 0 0 0 0 3 0 0 0 3 BA ES seers ap ioe rs oye eee Guinea pig 0 0 0 0 2 0 0 0 2 DO an se aS Se eae Boviness232. 2. 0 0 0 1 2 0 0 0 3 IE ec aera cs = Soles eee oats (aR See eae 0 0 0 1 0 0 0 0 1 IDO tres 2 fps Se eee Guinea pig 0 0 0 0 0 1 0 0 1 UAC AT eee SA tees, See eee doses 0 0 0 0 23 23 2 0 48 PAIS 27 Sea 5 ee See = ee do 0 13 26 58 56 23 5 0 181
When the mean temperature was about 83° F. larve were found to become quiescent in from 24 to 60 hours after dropping. Immedi- ately after becoming quiescent the tick begins to take on a light color at the anterior end.
Larve which dropped September 1, 1909, began molting on the sixth day thereafter. This was the shortest molting period observed. The mean temperature during the period was 88.29° F. and a total effective temperature of 272° F. was accumulated. The longest period from dropping to molting observed by us was 19 days. The mean temperature during this period was 70.5° F. The effect of temperature on the length of the molting period is marked. When the mean temperature was about 70° FI’. molting began between
THE ROCKY MOUNTAIN SPOTTED-FEVER TICK. 171
the thirteenth and sixteenth days; when the mean temperature was about 77° F. molting began between the eighth and tenth days, and when the temperature was about 88° F. molting began between the sixth and eighth days. Cooley reports (1909, p. 101) that larve which dropped during the latter part of July at indoor temperature at Bozeman, Mont., commenced to molt in as soon as 13 days there- after, and that the majority molted within three weeks. We have found that larve will often molt if removed from the host when only slightly over one-half engorged. The molting period of speci- mens which are not fully engorged is noticeably longer than in replete individuals. |
The last six lots, the molting of which is recorded in the accompany- ing table, contained. individuals from one-half to almost fully engorged. The length of the molting period was undoubtedly lengthened on account of the ticks having been picked from hosts before they were replete. The temperatures given with these lots are those recorded at the Dallas laboratory from the time the ticks were collected in Montana until molting began. The specimens undoubtedly experienced lower temperatures than those recorded during the few days prior to their receipt at Dallas.
TaBLeE LXXVIII.— Molting of engorged larvx of Dermacentor venustus.
3 Temperature Engorged larve molted—days following & | from dropping dropping. : ir) to date first Date = tick molted. engorged 5 larve Hast. a = is >| On dropped. = ! 31/8 /8/% 2 “4 | 3 ¢ S sisic=s @ | 6] 7] 8/9 | 10/11) 12/13/14) 15/16)17/18/19] - | £ | B sag 5 | a OM Die ee Z | = 3 = ee = a E a |lai< 1908. | | 2. | °F. ee 2 3} 0} O} O}| 0} OF O 00 OF 1) 1 O 0} 2) 85 70 mor. 66 |. .... Deans gatinds «5 0} Oo} OF OF} 0} O oO} 0} 2 2] 7 2 1) 614) 85 70.5 pes 6.)..... ee ee 27; 0} O} OF OF OF O 1; 5) 11) 6 2 OF O} 25) 85 70.4 iy Sak 2 Sa Se ee 17} 0} O} OF OF OF O 1 7 m2 2 ty O| 15) 8 70.3 iv" se? oe ORG te ha Pat 13} 0} O} O} OF OF O oO} 5) 8} OF OF OF 0} 13) gO 70.3 May 17|..... ae ee 15} O} OF OF} OF 1) 9 1) oO} OF OF OF OF OF 13) 87 77.4 May 18 |..... i ee oe Sen 10} O} OF} OF 1) 6 3 0} O} OF OF OF} OF O} 10) 87 77.6 July 15 |..... ie cee a3 76} O} O} OF 2) 26) 31 0} O} O} OF OF O} O| 659) 95 [76.5) 84.3 July 16|..... ee oat 43| O| 0} 4| 17] 20} 2 0} O| Of 0} O Of OF 43195 |76.5| 84.4 ge es _ eee 9) Oo} OF OF 5) 1) 1 0} oO} OF OF O OF O 7| 95 83.9 1909. eee 9. 6e NOS os -s - - ee 2 TE Se es Se ee ee ee es 3} 97 5) 89.7 Aug. 2 | Guinea pig........ Oo} 1; 1] 2 OF 1 a OO Oe <2 6,102 5) 88.57 pe ee ee a A a SE ee ee ee ee ee 7) 96 85.75 Aug. 29 ]..... ag eee PEE: 0} (2)} 22} 5) 5) 1 0} 0} OF OF O OF OF 33) 98 88.5 Aug. 30 ]..... a eee (})} 8} 21) 7) 2] 0 0} Oo} 0} OF OF} OF} OF) 688) 98 88.37 Aug. 31 |..... eS eee 0} 10} 30) 12} oO} O 0} O} OF} 0} O OF O} 52) 98 78.5) 88.18 Sept. 1 }..... ag, SS tse 2) 14) 27; 5) O} O 0} OF} OF} Of} O OF OO 48) 98 -5| 88.29 ee 5 a 0} 1] 0} O| oO} O 0} O} 0} 0} O OF O} 1) 98 J78.5) 88.32 Sept. 2 | Guinea pig........ 0} 12; 8} OF OF O oO} Oo} OF 0 0} O} 20) 99 .5 88.55 1910. July 42 Ground squirrel. .. o| 0 0 Of O} 1 0} 0} 12) 0 0 OS eT, Sarees 0} 0} O OF O17] OF 3} OF OF O 0} 0 July 222) Chipmunk........ o| 0 0 Of O 017] 0 | o Oo 0} 0 July 292%) Ground squirrel... o} 0) OF OF OF OF OF 6G 62 6.-../.. aa Aug. 102) Pine squirrel...... Oo} 0} OF OF 7] @)} 11) 1)-..]-...].. Aug. 142) Woodrat......... Oo} Oo} O OF} OF} O} 1) 1) O 1.
Ne SS SS eee ee
— ‘ . ——_—— ‘ ‘ ‘
1 The larve which molted on this day are included with those recorded on the following day. 2 These ticks were picked from native hosts in Montana and varied from one-half to fully engorged.
172 LIFE HISTORY OF NORTH AMERICAN TICKS.
The nymph (Tables LXXIX-LXXX).—The greatest nymphal longevity observed by us occurred in the case of a lot of 119 nymphs | which molted from larvee September 5-10, 1909. These nymphs, as also all other lots here recorded, were kept in the laboratory in tubes on moist sand. During the fall months 21 nymphs were removed from this lot and put on hosts, and during March, 1910, 16 were applied to hosts, 10 of these being applied March 18. On April 20, 1910, only one specimen was alive. This individual died before June 3, 1910. Thus it is seen that during the winter months a con- siderable number of nymphs lived for at least 189 days, at which time they were applied to a host and became engorged, and one nymph lived between 252 and 271 days. It seems certain that had none of this lot been put on hosts, some individuals would have lived considerably longer.t In alot of 12 or more nymphs which molted from larve April 19-21, 1908, 3 individuals were alive 178 days later. The last specimen died October 21, 1908, having lived between 183 and 185 days. One individual in a lot of 7 or more specimens which became nymphs July 24-25, 1908, lived between 137 and 145 days. All specimens in two other lots of about 7 indi- viduals each were found to have died between 56 and 75 days after they transformed to nymphs on July 25, 1908.
Among nymphs which were collected from hosts when slightly to one-third engorged, a longevity of from 47 to 122 days was recorded. The longest period—namely, 122 days—was observed in the case of one individual in a lot of 59 unengorged or very slightly engorged nymphs which were collected on a ground squirrel on April 12, 1910, at Florence, Mont., by Mr. W. V. King.
Nymphs kept in tubes in the laboratory at Dallas were found to be active most of the time at all seasons of the year while awaiting hosts. Occasionally a few individuals were seen to be grouped together and remaining quiet. These, however, were readily dis- turbed.
In most instances nymphs have been found to attach almost immediately after being placed on a host. Individuals have been found to attach to a host and become engorged after having been picked from another host when as much as one-fourth engorged.
Engorged nymphs have dropped as soon as the fourth day following attachment, the last leaving the host on the ninth day. This period is the same as that recorded by Ricketts (1908, p. 101). The en- gorgement period of nymphs which were collected on hosts when slightly engorged appears to be somewhat shorter than in the case of those nymphs which have not before been attached to a host. In two instances these slightly engorged nymphs have been found to
1 Since the above was written a record of nymphs living over 300 days has been made by us.
THE ROCKY MOUNTAIN SPOTTED-FEVER TICK. 173
drop fully engorged on the third day after application. The longest period required for engorgement, of these reattached nymphs, was 6 days.
TaBLE LXXIX.—Engorgement of nymphs of Dermacentor venustus.
do |
5 A ee ee Rabbit........ | 1 | “Spelt 5 cig te Sees ae 9 8 “ge Guinea pig... 6....... WY Pi a bee ope on 2 EL ee ae tae SS ae _ fee er 5 eee eee eee Pe 7
Sh ee eee | Bovine... ..... yi Bee ome, Fe peice lege tee Y, Saree 9 ee 3
| | 1910. | | | | | | |
a SS ee eee Guinea pig _ ees aaa 2 | 5 ep ae ee 5 oe ee re Squirrel....... J} eee gee 2 yr eee by. 22 7 hy jo eee eee ren Guinea pig <i EB! | oes Tie a Eee ae ae, 1 See | 1 3 ee Sa eee nee | Bovine........ i a eens Pre i Seen pe) sew |------ 4 Pa CRS = meee ei: Se ii. Lees ie dates) 7 ty Coleuel weer eer 8 1S eee, See oe Oe =P cs: TW ee ne 5 | ree) aes ERS ISS eS. Lea. @! S Ss eee bates ee Sieh 9 sions | 8 3 ae cae Base il Te i eo Guinea pig 30 | ie yee gett Peete S837 22 NO | eee ee eee ele Rabbit... ... - aes U4 es 5 cH) Ae a Ve ie ee 1 7 JN TOP ah i ee Guinea pig... -| Mt Sergey (ere see 4 ed Bes Oe | ee | 8
Total st ls. +198 |... wag. aR oe | Meta) bastel. Lose: (ee 154
< These individuals were collected on hosts when unengorged or slightly engorged and reattached on this te.
In our observations engorged nymphs molted in two instances as soon as the eleventh day after dropping. The first instance occurred in a lot of ticks which dropped August 6, 1908. The mean tempera- ture during this period was 87° F., 485° F. of effective temperature having been required for this transformation. Most of the ticks from this same lot, which dropped on the same day, molted on the fourteenth, fifteenth, and sixteenth days. The second case, when a molting period of 11 days was observed, occurred with a nymph which dropped July 21, 1910. The mean temperature during this period was 89.5° F. and the total effective temperature was 511° F. There is a great variation in the periods required by this species for molting. Thus of 3 engorged nymphs which dropped May 20, 1908, 2 molted to females on the seventeenth and eighteenth days, while the third did not molt to adult until the forty-ninth day after dropping. A still more marked variation in the molting periods of a group of ticks was observed in a lot of 3 nymphs which dropped October 3, 1909. Two of these molted on the eighteenth and nine- teenth days after dropping, while the third did not transform until March 22, 1910, or 170 days after dropping. Both of these lots were kept under identically the same conditions and all appeared to be fully engorged. In the second instance the molting of the last nymph
174 LIFE HISTORY OF NORTH AMERICAN TICKS,
was undoubtedly delayed by the approach of cold weather, but the first instance, as well as other similar cases of variation in molting periods, are difficult to explain. Cooley (1909, p. 101) found nymphs which dropped August 12 to commence molting in 42 days, while others required 47 days. Ricketts states (1908, p. 102) that the period required for molting varies from 1 to 3 months, according to the temperature.
After dropping, the nymphs remain rather active for from 3 to several days or even weeks, depending upon temperature and state of engorgement. When it is cool the activity continues for a longer period than during hot weather and partial engorgement has the same effect. The nymphs usually become inactive gradually and within a few days after complete quiescence the area around the anterior end and the antero-lateral borders begins to become white. Dr. Ricketts has found the engorged nymphs to remain active in Montana during July and August for from 2 to 4 weeks, while if placed in a refrigerator they remained active for as long as 3 months. The sexes can often be distinguished several days before molting occurs by the appearance of the color pattern of the adult showing through the skin. In one case the female shields were easily seen 6 days before molting took place. Some days prior to molting the surface of the body of the engorged nymphs frequently becomes dotted with small drops of a yellowish transparent fluid exudate.
Molting is accomplished in the same manner as observed in other species of Dermacentor. The old skin first becomes free from the body at the anterior end, then splitting occurs on each side just above the third pair of legs. Later this splitting extends forward on each side to the lateral angles of the scutum, where the splitting follows the edges of the shield and the two fissures meet at the tip of the scutum. In many cases the force exerted by the tick causes ~ the splitting to extend back around the ventro-lateral margin so that the skin is broken in two. In other cases the lateral fissures extend backward along the dorso-lateral border to the second festoon grooves where they follow these grooves toward the venter, the dorsal end of the skin forming a hinge which allows the escape of the tick.
The length of the molting period of nymphs which transform to males and of those which become females is about the same.
THE ROCKY MOUNTAIN SPOTTED-FEVER TICK. 175
TasBLE LXXX.— Molting of engorged nymphs of Dermacentor venustus.
Engorged nymphs molted—days following dropping.
an tect e gor SER a eS ee dropped y 11] 12 |13| 14 | 15 | 16)17| 18 |19] 20] 21 | 22) 23 | 24) 25) 26) 29) 30 | 31 1908. May 18] Bovine.....-- 7 «ada | | Sass RE, Pe tS fara May 719-1: . 2. (CS a See 2 ASS eS | rN pa ees Mise: 28 iE es: ae 2-52 2 | Ee] | SA ON Na eee ee May. 21. 1°. oo: ee ee Ze, + Ra BRE Se a el aS ABE Gil owe: €6..55.(35: E7IEOUES. ee po a ee Se Pe TA CAC ctocel 1909. Agr. 18/) Gaines pigs: .) Of. 12-1. - 2 ee ee Sept. 15 | Rabbit....... = FAL eg ORE RE a ee Os re \ Oct. 3 | Bovine......- | Lge) | Ie | (pel ee oes (ee een! ee 1910. Mar. 10} Rabbit......-. 1
Sey NESTE 5” ERE GR ie AG Cans SEA Spr Seeman a eS Se al ae Wee ee Set ee pe (eee Apr. 14!) Ground squir- en cremate me es te isch Re ae a ae May 161) Ground squir- \25 ,
5 nr, : - (seen Peele hae May 30] Bovine....... 3th eee alae hel pee sl ee fe Se es ee ee eel (oe UR on Soe ee te etait (etek ete Ghee Biciae tr boo Gi
June 13! giecag | 16
CULE 1) TEATS Ta FIP || ees ee Ve ees (ee ears ee eee Peers eee ames eee (eee eee) Mees - 5. July 261) Ground squir- \10
Open ee ere ke le tae io earls pe te he ee CO gO a a eee eee Aug. 1] Rabbit.....-- 1) eee 1g Aug. 11 | Guinea pig...| 3)/...| 29]... Aug. 18 | Rabbit......- Meus idtsc: Doe...) Guines pig. |..| 7i..}--- { 38 Aug. 19|..... ie a 12 29{S 33 Aug. 30 |..... ee ee "7 ae ee {id Sept. 28 | Squirrel...... ee Same ee! SEES CORRS PE ee Bee ull 5 CaS RR A Se Sse SAR eg SN ae
1 These nymphs were collected on native hosts in Montana when from one-half to fully engorged.
176
TABLE
LIFE HISTORY OF NORTH AMERICAN TICKS.
LXXX.— Molting of engorged nymphs of Dermacentor venustus—Continued.
Temperature Engorged nymphs molted—days following drop- | Number | from dropping ping. molted. | to date first tick molted. peer gorged nymphs Host. = dropped : J 2 Sa & | 32) 33| 34 | 35] 37| 40) 41| 42 | 43/46] 49/61] 71170) | 3 —|3/as S ol Sis & & gE = a gis ia Soe OO Sea AZ ala|e| a | (<4 1908. hers OP kgs Ane May 18] Bovine....-.-.. 4b gees Aes ees eget | A | satel fore) ies allies 1} 1) 2) 88.5/68. | 78.6 May 19): --.: doses stone 6} - lebeliocellosel|Socllsaae MONEE Slee 2} 2) 4) 88.5)68 | 79 May 20|..... tne eee holt He ees eee se leete| see Gealecis Pee O| 3] 3] 88.5/68 | 79.1 May 21]..... ie Al. walt Ole ioe ie ES 1} 2| 3] 89 |68 | 79.2 AU |Gillesece GOS e ses SFA I ST =| PA Tee Save s}0d 3); LG OSM aia edank JNU hail fa Vee Shear (oo eae eee 13) <2|| Sse sss tealee = -| 10} 2} 12) 99 |73 | 86.5 1909. | ANIS= 180] Guineas pigs |p lsc oe oleae sel ---| 1} O| 1/103 |77 (88.52 Bent. was) anita. ss hocklt Olesa tee PAN ase Se ee hee ieee cierale .-| 3] 2] 5] 95.5156 177.45 Oct... 3.| Bovines:.: =... SSI cit She les ek ate ea 1d} 3) Of 3) 92.5)52.5)73. 25 | 1910. | Mar. 10| Rabbit........ 1 Ree ee cy DP ae ees ..-l1g}.--} 1] O} 1] 92 [43 170.55 perk at rahe oe a pid Bete ae | eh aia | 19 setpcain sg U6 9] es ese 1} 1] 2) 89 [43 |70.80 Apr. roundsquir- 1d 2d P ee Vig)... eae 192g o{pgps ht 3| | 11} 91 {43 70.86 May 5] Foxsquirrel..| 5/1Q/1¢ {$}\.. aoe 2} 2! 4l100 |59 |76.27 capt doe 4 (pao mapa eaten nS }-|-Aah Ris: Beheeie bale Paaais 10| 12} 221100 60 |s1.69 May 30 Bost wee otek BN Se Bs toe Ge | ay an aD Ae ae 1} 2} 3/100 |66 |86.98 June 131) Ground squir-
Weloeee ese WGPs ase | Reese Saleen ates se es cee 2 roe pend ee ett erie era eer 6| 7} 13) 98 |69. 5/90. 63 duly 20. | Guines pigh-..|) 12. -|-2<)-2-)2| ool oo |peel eee nie eee eee o) setae 1} O} 1/104 |77.5)89.50 July 261 re ae squir-
ee eee Wee il coc savoir Seale See cleeal eee 3] 7} 10/104 |79 |90.80
July 291 Waddonncien: OE ss S| 2 Mt CR me A ee fl Et aa | an 1] 10] 11]104 |79 |90.07 Use TO Rappibse-- sec a) ae VS te ieee yf, Nf eee Fe | fst 44 1) 5/103 |79 {91.27 AUP LE iKGuines pig acss|l Slso4|os5|e acl esate leen| eee eee ees eee eee eee eee eee 1) 2| 3/104. 5/81. 5/92. 54 AUPE Vs) Sea ibs se acer A exteledel ees eSalecelsules 15 of ae tel | eee pes be 2) 5} 7|104.5)73 |88.96 Dols} Guinea pig ss sala se eclse eo) Sse toe all eee | Sees eet a eee eal eee 2) 5) 7|104.5)73 |88.94 Auge WN. J. 6 (oy Ate eae 14 Fa VU Fem) UY Paar) el be || ee eb 5| 7} 12|104.5/73 |88. 85 AIP SO lees Contec cee 5) (pe (RE eee | Se ae ee) FS 8 (Reel Ke S| | cee a 4| 2) 6) 98 |72.5/85.62 Sept. 28 | Squirrel....... 1 ea a es RE SN lek | ae ee fe O} 1) 1} 91 |54.5/77. 68 a a ee a es SE ee eee en eee
Total..... i fare age ee fet Lu! | ie (ew ea |, =| Sl | a seal ee 79| S9|168|..- -c)e 2 ieee
1 These nymphs were collected on native hosts in Montana when from one-half to fully engorged.
The adult (Table LX XXT).—Of 355 adults, the sex of which was determined when they molted from nymphs, 172, or 48.5 per cent,
were males.
Immediately after molting both seXes are rather plump;
the voiding of numerous pellets of white excrement begins almost immediately, and within a few days the thickness of the ticks is much reduced. The voiding of excrement continues for some time, but the amount is greatly decreased after the first few days following molting.
Partial feeding in the nymphal stage has a marked effect on the resultant adults. The size is frequently reduced by more than one- half, the color pattern is often very weak or does not appear at all, and certain structures are affected.
The longevity of the adults of this species is remarkably great. One male in a lot which molted to adults in June, 1908, lived between 188 and 197 days. Three lots of ticks which molted between August
THE ROCKY MOUNTAIN SPOTTED-FEVER TICK. 177
22 and August 25, 1908, lived between 250 and 290 days. The greatest longevity among a large number of lots of ticks which became adult during 1909 was between 320 and 353 days. This record was made on a single male which molted between August 30 and September 1, 1909, and died between July 18 and August 18, 1910. The other lots which became adults during 1909 lived between 117 and 321 days. Among over a hundred lots, the molting of which was observed by us during 1910, the longevity ranged between 66 and 367 days. The majority of these lots contained some individuals which lived over 250 days and a considerable number showed a longevity of over a year.
Still more remarkable is the longevity exhibited by lots of adults collected in Montana during the spring of 1910 by Mr. W. V. King, before they had attached to hosts. Among the several lots observed the longevity varied from 55 to 413 days. Four of these lots which were obtained from shrubbery between March 18 and May 31, 1910, lived more than 320 days. The greatest longevity observed occurred in a lot of one male and two females collected at Victor, Mont., April 2, 1910. One female lived until May 20, 1911, or a period of 413 days. It should be borne in mind that these collected individuals undoubtedly came to maturity in the fall of 1909 and passed the winter in hibernation. Therefore we should add about six months to the longevity observed, making a total longevity of about 600 days. It is thus apparent that ticks which become adult in the latter part of the summer may survive until the second spring following. Adults collected from animals during the spring and summer of 1910 were found to live between 40 and 262 days. The females in these lots varied from unengorged to about one-eighth engorged. The length of the life of the sexes appears to be about the same.
All longevity records are based on ticks kept in tubes on moist sand in the laboratory.
There is a marked tendency for adults which are awaiting a host to climb to a considerable height on shrubs or trees so that they are in a position to be brushed off by large animals when passing. When disturbed they either grasp any passing object with the forelegs, or curl the legs up, drop, and catch hold of any object which they happen to strike in falling. When one moves an object near speci- mens which are awaiting a host, the ticks begin to extend and wave the forelegs, the other legs also being frequently extended. Engorged females also use the legs for feelers in their search for suitable piaces for concealment In one case an engorged female was observed to extend and wave all of the legs but one, which was used to cling to the inclined surface upon which it was crawling.
21448°—Bull. 106—12——12
178 LIFE HISTORY OF NORTH AMERICAN TICKS.
Newly molted adults show no desire to attach to hosts. In fact, the habit of attaching to hosts in the spring months only is so firmly fixed in adult ticks of this species that it is very difficult to induce them to attach to hosts at other seasons of the year. We have observed both sexes to remain motionless in tubes in the laboratory for weeks and even months at a time During this resting period the ticks usually keep tho legs closely curled up to the body and it is often difficult to induce activity.
About twenty trials were made between September 1 and December 15 to secure the attachment of adults which had matured the preced- ing spring. Bovines, guinea pigs, and rabbits were used as hosts. In only two instances were any specimens induced to attach and in neither of these cases did engorgement or mating take place. In one of these instances 3 females and 2 males attached when applied to a guinea pig on October 4, 1910. All of the specimens changed their points of attachment a number of times, but no perceptible engorgement took place. One of the females remained on the host until December 22, or 79 days, and the male did not disappear from the host until a few days later. During the early spring months no great difficulty was encountered in getting adults to attach to guinea pigs, rabbits, goats, or bovines.
When placed on a host the adults usually crawl about carefully for some time before attaching. On small mammals they attach to any part of the body, but on large mammals, in nature, we have found them to attach mainly between the legs, along the escutcheon, belly, and dewlap, and sometimes on the shoulders. On horses they frequently attach under the jaws and sometimes in the mane. In one instance a number of males and females were placed on the legs and dewlap of a yearling bull at 4 p. m.; by 5 p. ma considerable number of them had reached the animal’s back and were crawling about there. The next morning all of the specimens that could be found (3 males and 7 females) were attached on a small area on the top of the shoulders.
Mating occurs on the host. We have not observed a male to attach beneath a female before it had fed for at least 4 days. Usually a feeding period of from 6 to 8 days appears to be necessary before the males start in search of mates. The males have been observed to insert their mouthparts in the genital opening of the females immediately after passing beneath them. In one instance, at least, the palpi of the male were not inserted with the hypostome. The act of copulation appears to occupy only a short time, probably less than an hour, then the males attach close to their mates, the ventral surfaces together, and the legs of the males clasping the legs or body of the females. It seems quite certain that copulation takes place more than once while the males remain beneath the females. Ina
THE ROCKY MOUNTAIN SPOTTED-FEVER TICK. 179
number of instances males have been observed to remain with females until the latter had become engorged and dropped, when they sought other mates. As many as three females have been seen to be fer- tilized by a single male. In many cases the females are nearly engorged before being visited by a male. Some of our observations indicate that the males usually start in search of mates in the early morning or late in the evening. Males have been observed to remain on a host for two months, at the end of which time they were removed. During this period two successive lots of females were applied and engorged, the males fertilizing both of them.
The period of engorgement at Dallas, Tex., varied from 8 to 17 days. After fertilization takes place engorgement appears in most cases to proceed more rapidly.
TaBLE LXXXI.—Engorgement of adults of Dermacentor venustus.
| Females dropped engorged—days following | Date | ee application. Total females | Host. ae number applied. | : F dropped. | 8 9 10 11 12 13 14 17 May 15,1908 | Bovine............... 2 ef sR 4 eg od GR Dc, a ay Be ied Dae Parr | 2 June 15,1909 |..... Pt eee | ot ae Pet IE ge ke 1 eines A Lee 1 Mar. 19,1910 | Guinea pig!.....--.-- uses 1h al ee | eee eo Hy Seve? 1 Mar. 29,1910 |..... (OR See ee ee 1 US Peers Seer ee ae feeetios bate cet |. he 1 fn, “aaee0 | BOVINE. .2 22. 2-...... MY atts Fel sae eat liers soe 2 a eee eee fc oe 4 Apr. 13,1910 |..... PEE Eee Ae oe 1 oe See ee ee ee ee one ee) ee 2s ben cee 1 Apr. 15,1910 | Guinea pig. ......-..- Ate ae cleanin 3 eens = NH eee ee alle [Sooo Pris 2 1 Bray 48,1900 | Bovine.....-......... 3 Mich cay A S| eo ee Pmt de De tees hx bei. 3 sry 26,1910 | Rabbit.........5..... ae ae tae Ned Oe) ek Poe bape 1 Mh Syl 3 1 mar 204914 | Bovine. ..------<-.6.- Ve eee 5 ISOS. cee. S. | bee a RSE es 7
LIFE CYCLE.
The larve have a longevity of about 2 months. They engorge in from 2 to 8 days after attaching to a host and may molt as soon as 6 days after dropping, a total effective temperature of 272° F. being required for this molt. Nymphs may live for more than 300 days. They engorge in from 4 to 9 days after attaching to a host and they may molt as soon as the eleventh day after dropping, a total effective temperature of 485° F. being necessary to produce this transforma- tion. Adults have been observed to live for 413 days and since this record was made on ticks which were collected in the spring, they must have had a total longevity of about 600 days. Females may engorge as soon as 8 days after finding a host, commence depositing eggs as soon as the fifth day following dropping, and deposit as many as 7,396 eggs. Embryonic development may be completed in 16 days, an effective temperature of 614° F. being required.
It appears that the life cycle of this tick usually requires 2 years. The winter is spent in the unengorged nymphal and the unengorged adult stages. The adults begin to emerge from hibernation soon after the snow disappears. The great majority of them attach to
180 LIFE HISTORY OF NORTH AMERICAN TICKS,
the large mammals between March 10 and June 10, then engorge and deposit eggs from which larve hatch. These larve engorge upon small mammals and drop and molt to nymphs which, in some cases, May remain quiet until cool weather begins and then go into hibernation to appear as unengorged nymphs the following spring. Others probably become engorged and in the fall produce adults which pass the winter in that stage. The over-wintered nymphs appear somewhat later than the adults; they attach to small mam- mals, become engorged, and produce adults. The majority of these adults probably remain quiet during the summer and go into hiber- nation the following winter.
ECONOMIC IMPORTANCE.
While this species appears to be quite abundant in certain portions of the northwestern United States and more or less annoying to domesticated and wild animals, it is of particular importance because of the réle it plays in the transmission of the causative organism of Rocky Mountain spotted fever. This is a disease of man which occurs in several of the Rocky Mountain States. Itis of extreme importance in the Bitter Root Valley of Montana, where a number of cases occur each year, among which the mortality is usually about 70 per cent, In Idaho, however, the disease is much less virulent, the mortality not running above 5 to 8 per cent, although the number of cases in the southern part of this State frequently exceeds 300 per year. The occurrence of the disease is largely eonfined to the spring months March to June inclusive, or the period during which the adult ticks are most active.
NATURAL CONTROL.
Few observations relating to the natural enemies of this species appear to have been made. Chickens have been found to devour the engorged females with avidity when the ticks were fed to them. No doubt fowls eat a large number of ticks which drop from animals in the barnyard. In Colorado a species of blackbird was seen to devour the engorged ticks as they fell fromcattle. Engorged females have been observed to be eaten by tame rabbits upon which speci- mens were being engorged. The little black ant, Monomorwum minimum, was found on a number of occasions to have entered pill boxes which contained engorged larve and destroyed dozens of specimens.
ARTIFICIAL CONTROL.
As has been pointed out, the adults of the Rocky Mountain spotted- fever tick feed almost exclusively on the large domestic animals, while the small rodents are the principal hosts of the immature stages. This immediately suggests the idea of destroying the adult ticks on domestic animals. On account of the fact that many of the adults
THE PACIFIC COAST TICK. 181
which appear in the late summer or fall from overwintered nymphs will hibernate before engorging, it will be necessary to continue the treatment of the hosts for at least two seasons. Dipping, swabbing, or hand picking would probably not be necessary except between the first appearance of the ticks in spring and June 15. As has been pointed out by Dr. Ricketts, the destruction of the smal] mammals which act as hosts for the immature stages would also aid in lessen- ing the numbers of the tick.
THE. PACIFIC COAST TICK. Dermacentor occidentalis Neumann.
The common name of this tick is derived from the fact that it is known to occur only in the Pacific coast region of the United States.
DESCRIPTIVE.
Adult (Plate XII, figs. 8-12)—Males 2.8 by 1.6 mm. to 4.2 by 2.3 mm. Females, unengorged, 2.9 by 1.8 mm. to 3.6 by 2 mm.; engorged, 9 by 6.1 by 3.3 mm. to 11.8 by 7.6 by 5.6mm. Unengorged males and females reddish brown, scutum in both sexes well covered with a whitish color resembling bloom, somewhat iridescent, interrupted by many red punctures; the same color on dorsal side of legs as on scutum. Engorged female steel-gray, dorsum with an olive-green surface color, which covers the gray except in small spots, thus giving a mottled appearance.
Nymph.—Unengorged, 1.13 by 0.63 to 1.26 by 0.65 mm.; engorged, 3.10 by 2.16 by 1.11 mm. Color light brown, lateral portions of scutum darker, the intestines, which show through, dark brown. Capitulum 0.32 mm. long (from tip of palpi to base of emargina- tion of scutum); scutum 0.488 mm. long by 0.557 mm. wide.
Larva.—Unengorged, 0.643 by 0.426 mm.; engorged, 1.316 by 0.916 by 0.603 mm. Capitulum 0.139 mm. long (from tip of palpi to base of emargination of scutum); scutum 0.23 mm. long by 0.339 mm. wide. Color, unengorged, reddish brown; engorged, bluish gray.
Egg.—Ellipsoidal, amber to brown in color, shining, smooth. The maximum size of 10 eggs was 0.517 mm. by 0.402 mm., the minimum size 0.502 mm. by 0.387 mm., and the average size 0.51 mm. by 0.395 mm.
HOST RELATIONSHIP.
The host of the type specimen is the deer. As yet little is known regarding the hosts of the immature stages. They attach and engorge readily upon guinea pigs, rabbits, and bovines. Over 80 lots of adult ticks, in which the host animal was given, have been received from correspondents. The frequency of occurrence on
182 LIFE HISTORY OF NORTH AMERICAN TICKS.
different hosts was as follows: Cattle, 30; horse, 22; man, 16; deer, 4; mule, 4; dog, 3; ass, 1; rabbit, 1; sheep, 1. While cattle, horses, and man are the hosts upon which most of our collections have been made, deer act as hosts for large numbers of adults. In some eases they are said to be infested with thousands of specimens.
GEOGRAPHICAL DISTRIBUTION. (Fig. 15.)
The type locality for this species is Occidental, Cal. Although this species has been reported from Texas, New Mexico, and Arizona, as well as California, it is very doubtful if the records from Texas, New Mexico, and Arizona are correct. Our records indicate that the species is confined to the Coast Range and Sierra Nevada Mountains in Cal- ifornia and Oregon and the small mountain ranges in southwestern California. The species occurs in great abundance in the extreme southern part of California, and it is therefore almost certain to occur southward in Lower California and western Sonora.
LIFE HISTORY.
No previous work seems to have been done on the life history of this species. Investigators of Rocky Mountain spotted fever have published a number of notes regarding the life history of Derma- centor venustus under the name Dermacentor occidentalis.
The egg (Table LX XXIT).—In the laboratory in June, at a mean temperature of 87.19° F., deposition began in one case in 4 days. In April, with a mean temperature of 66.18° F., one tick had a preovipo- sition period of 14 days. The longest preoviposition period actually noted was 17 days. This record was on a female which was collected and mailed to the laboratory, hence the temperature and moisture con- ditions were notnormal. The average preoviposition period of 4 females dropped in April and May was 7? days. The average preoviposition of 17 lots of females collected during the period from March to June, inclusive, was 10.4 days. During April and May, 4 ticks showed a deposition period of from 27 to 39 days, with an average of 314 days. The mean temperature during the shortest period was 74.17° F. and | during the longest period it was 70.99° F. These females died in from 1 to 7 days after deposition was completed. The average number of eggs deposited by the 4 females was 3,210 and the maximum number deposited by an individual was 4,555.
The minimum incubation period under laboratory conditions was 21days. This record was made during June, 1910. The total effect- ive temperature required for embryonic development appears to be at least 842° F. The last two lots of eggs, the hatching of which is
THE PACIFIC COAST TICK. 183
recorded in the following table, were kept in an incubator during incubation and removed therefrom when hatching was complete.
Fig. 15.—The Pacifie Coast tick, Dermacentor occidentalis: Distribution in the United States. The large dots show localities where the species has been collected in our investigation. The small dots show the probable range of the tick. (Original.)
The incubation period was reduced to 16 days in these two instances, during which time the mean temperature was about 90° F.
184 LIFE HISTORY OF NORTH AMERICAN TICKS.
TaBLE LXXXII.—Preoviposition, incubation, and longevity of larve of Dermacentor
occidentalis. fg Temperature during incu- Mini- bation. D i Hes L 1 Date engorged female | ;,°P°S' | Hatching| Cu aie dropped or collected. ODE began. | 22 Ai larvee'dead.: tne Aver- gan. tion GO teescal ier) oe Total e- ge | effec- o d mum.|mum.| daily F od. mean. tive. 1910. 1910. 1910. | Days. 1910. DOYS aelien | oop gis oF, SDE 2 EKeolisered) weer Apr. 15 | May 19 35 | Before July 16. 58—| 91} 43 70.16 | 950.6 BS anceineee esc Apr. 14] May 17 34 | July 16-Aug. 4.}105-124 91 | 43 70.72 | 942.48 Apr. ei (collected)... .- Apr. 21 | May 25 35 | July 18-Aug.4.} 5471 91 | 43 71. 43 |1, 012.0 Apr. 12 (collected)....- Apr. 26| May 26 | eta GO se ae 53-70 O91 | 52.5) 73.19 | 935.75 Apr. 13 (dropped)....- Apr. 27} May 28 32 | Before July 18. 51—| 911] 58.5] 74.23] 999.50 May 3 (collected).....- May 10] June 16 38 | July 18-Aug.4.} 32-49] 100 | 59 77.92 |1, 326.9 DOS: teach eeenes May 13] June 7 26) leases do .2Sesesce 41-58 | 100 | 59 77.07 | 885.75 May 9 (dropped)....... May 16] June 10 26} Aug. 4-12..... 55-63 | 100 | 60 79.28 | 943.25 May 11 (collected).....} May 20] June 12 P.O (ee See GO ae 53-61 | 100} 60 80.09 | 890.25 May 13 (collected)..... May 23] June 14 23 | July 18-Aug.4.} 4461] 100 | 60 80.25 | 856.75 May 15 (collected)..... =| es, 24 | June 16 DAW Eos .2 dogssces-8 - 32-49} 100 60 80.71 | 905.25 May 29 (dropped).. June 4] June 24 7 eee dOessccacse 24-41 97 | 66 83.1 842 June 20 (dropped)... Lscene June 24 |.July 14 21 | Aug. 12-20....| 29-37 98 | 73.5 | 85.7 896. 75 Noy. 15 (collected)... .. Dec. 12'| Dec. 27°) 116 | Mar.18) 1911... 81s rel cemeees 90" Hue aee (about) WOM ser woes eee e Dec. 16} Dec. 31} 116 | Mar. 14.1911... Laid ie etre || Seeate Ue eeces 2c (about)
1 Kept in incubator during incubation.
The larva (Tables LXXXII—-LXXXV).— The longevity of the larvee of this species is somewhat shorter than that of most of the other species of the genus Dermacentor. The greatest longevity accu- rately recorded occurred in the case of a lot of larvee which hatched May 17 and on subsequent days. The longest-lived larve of this lot died between 105 and 124 days after hatching began. A large number of records of larval longevity were made on the progeny of individual ticks. In the majority of the lots all larvee were dead within two months after the hatching of the eggs began. All of the records on longevity were made upon larve kept in tubes with cotton stoppers, on moist sand in the laboratory.
Engorgement may be completed as soon as 3 days after attach- ment to a host. The greatest number of engorged larve dropped from the host on the third, fourth, and fifth days after attachment. A single larva was found to have dropped the second day, but since this specimen was not fully engorged it is quite probable that it was rubbed off by the host. This statement probably applies to all larvee which were found to have dropped before becoming fully engorged. The longest period required for engorgement was 7 days. In most instances larve were found to attach within a few hours after being applied to a host. In our experiments only a small percentage of the number of larve put on a host ever reached engorgement.
THE PACIFIC COAST TICK. 185
TasLe LXXXIII.—Engorgement of larve of Dermacentor occidentalis.
Larve dropped engorged —
Date eS days biee in: application. ee
lary, Host. pheny we eT! State of engorgement. applie <2
sed a | 3 | 4 | 5 | Lar Pe
/ } 1910 May 24] Bovine................- 1,000] 0} 1/38|10| 3]....[.-.. 52 | Two-thirds to fully. June 10 }..... __ a a a ect ee RPS ed eS eo a ee ee 33 | Fully. June 21 |..... = EO ae ee 400} 0| O| 0} 0O| 2 | re re 2 (?) ie a Ss Soe rep) Se Oy OP TE ae eee 22 y- July 6] Guinea pig.-.......-..-..- 500 | 0} 0 |130 | 60 (206| 4 400 | Two-thirds to fully. Boe Pe OvINe =... 22352 = 5 Se ee Oe Ne ih tk 6 | Fully. July 19 |. -.. A ee eee 200}; 0; O; O| 8{| 6] 1 15 | Two-thirds to fully. ED Fes oe oa al ea eee 4 Le] calif aN (a el ee] eel eee ae 4| Fully. Aug. 25 | Guinea pig............. 50! 0] 0] 0] 0 | 0} 4) i} 15 Do. i
TaBLE LXXXIV.—Rapidity of engorgement of larvx of Dermacentor occidentalis applied to guinea pig at 11a. m., July 6, 1910.
Period | Percent-
Engorged larve Engorged larve ; dropped Number. iederd —< dropped Number. e ie re i (tray examined). cation. | dropped. (tray examined). cation. | dropped. Hours Hours
July 9,9a.m...... 6 70 1.5 || July 10,— p.m. 35 (?) 8.75 July 9,2 p.m.....-. 10 75 2.5 || July 11,9a.m..... 117 94 29. 25 July 9, 4.35p.m.- 90 77 22.5 || July 11, 11.30 a. m.. 7 963 19. 50 July 9, 5.05 p. m.... 19 7 4.75 || July 11,5p.m..... 11 102 2.75 July 9, 5.30 p. m...-. 5 784 1.25 |] July 12,9a.m..... = 118 1.00 July 10,— p.m.... 25 (?) 6. 25
In July, at a mean temperature of 86.82° F., molting began in 6 days. This transformation appears to require a total effective tem- perature of 263° F.
TaBLE LXXXV.— Molting of engorged larvxe of Dermacentor occidentalis.
Engorged larve Temperature from molted—days fol- dropping to date first lowing dropping. tick molted.
#4 Total Date engorged larve Num- Host. numbe dropped. ber. | molted. Aver- ad 9 e 6 r| 8) 9|30|21) 12 daily | mean. | ’ ’ 1910. | = fe
May 27,a.m........... Bovine.. 3gi...|..- | 5 ()| 25] of 2 32 83.47 Cie, SE ea ee (eee "ie 10. ee ees | ee 4 83. 57 Se es ee phages | 3. am EY Mies aes Cat 1 84. 04 a eta! lala F 6a a 3] “4 3] 10 83.05 oy a do... 31 aes | PR 3} 4 83. 05 ee ee ae do..... 6| Pi Be a aes 4 84. 52 og. ly a ee beet GGsc cree a. 5 eel je = eS eel 7 86. 64
LTT gt eae aia aan aaa Guinea pig... tS) Cy UBis. oh ci 16 86. 4
a) a eee ee aa. -.. oe Ee 3) Ree Rad gl 15 86. 4
SO SSR e a RE do... 24\...)... (iy) o4}...f.. |... 24 86. 4 ge ae eee do. 25 (@)} 1 19 86. 78 LE A eee ae do. 117} (*)!100 100 86. 82 LT es ea do. 89] (1)| 78] O} 2)...]...]... 80 86. 82 8 eee Se do. ay GE RS 2 86. 83 ie: SS ae Bovine........ 4 uy | oan ee 4 87. 75 oe {CO ere 0 a ee a 4 89. 29 Se eee Pe do ee 1 92. 37
i) 6 aS a SS ae | AR ie RE: aad OR 3 87.3 ye eee ae 2 ES 6). 5 a ee 5 87.31 ie ae ; Se 4\. : . a aR 2 86. 16 Total....| 481|... | ao) Qa eae; eS —
1 The lary which molted on this day are included with those on the following day.
186 LIFE HISTORY OF NORTH AMERICAN TICKS.
The nymph (Tables LXXXV-LXXXVIT).—The longevity of the nymphs of this tick is shorter than that of any other species of Der- macentor studied by us with the possible exception of those species which molt on the host. The records made indicate that during the hot summer months the longevity ranges between 40 and 60 days. The greatest longevity observed was between 76 and 108 days. This record was made in the fall months. These nymphs were kept in glass tubes with cotton stoppers on moist sand in the laboratory. It is probable that during cool weather a somewhat greater period of longevity would occur.
TaBLE LXXXV.—Longevity of nymphs of Dermacentor occidentalis.
Number
Date larve molted to nymphs. Number. nel on All larve dead. gate ost. ; 1910. 1910. Days.
TMNG ABE oe Ne oASo eek ees see eeeeee 37 Onl tulyTSitoyAueraee see cess 40-61.
MUITNO 2124 Me cee eoceeies seaman dee 18 0} Aug. 4to Aug. 12............| 41-52.
AFL gel WE 0 pele eae iies Sree etme ee Aa 300 230 | Aug. 12 to Sept. 24.......... 23-69. July/SUto re ie ee at nce eemee es 4 0) ‘BeforeiOch26 2 5--255---4--- Less than 75. PANTO il {ian Se me eee eee. ee 1 On Sarre GOS ers edenee csc eeemeee Less than 70. NODES GLO ie Hae oo etic ccs eects 10 0" | Nov, 200 Dees 23)... 2252 eee 76-108.
TABLE LXXXVI.—Engorgement of nymphs of Dermacentor occidentalis.
By uphs ed Dette fol- | Total owing application. num- D hs Num- pete els S Host. ae re State of engorgement. 3 | 4°)-50) 6.127 1|-8.) 90 | meee 1910. Sly Qo pe see Guinea pig..-.} (?) Sal Sal oul seaal eee sales 20 | Fully. Suiliy: 2655 ees Ses (Meee dome sec SOUS. eaeeilectes Cha Pain Tat es Lat 10 | One-fourth to fully. Tulys0s waseeeeeteee Bovine... ---- AP eee eel sic 1 ees bere ete 1 | One-third. PANTER GSTS. See abbit.s-e- ase 200! | Sa eLD aS 2e ELS) | Sates 2 72 | One-half to fully. PANTIE. Ould ee ae 2 Guiness, pigs = SiG?) lee neleeee DEN RS ANS Shieh all ap eS 2| Fully.
1 These lots were accidental infestations, hence the exact date of attachment is not known.
The shortest period of engorgement accurately observed was 4 days; the longest, 9 days. In the last instance the nymphs were still only about one-half engorged and were probably scratched off by the host. The weighted average engorgement period of all nymphs upon which accurate records were made is 5.56 days. Attachment was observed to take place, in most cases, almost immediately after the ticks had been placed on the host.
THE PACIFIC COAST TICK. 187
Taste LXXXVII.— Molting of engorged nymphs of Dermacentor occidentalis.
| Temperature from dropping to date
Engorged ey molted—days | Number P first tick molted.
follo ping. molted.
Date engorged -
: Num-| | > — drop- Host. har. 3 by | z e = Bs = e 1og |13/14| 15 | 16 | 17| 18 | 19 21| 22 F = | 23 |8¢ siSiai = 5/26 Pag tales «1 oe ee | f= | Siaje|l 3 | 3 |< ‘sccuems tel Gaal Feel ees el ee ed es i aid ean 1910. | ' et pis | | | | oF | oF. Bez June 12, p. m....! Guinea pig--..| U-..|--=|----|----]----|----|---]---|1 9]... i) 7 103 bes 90. 10 July 22,a.m....\..... Pies! 4 = 1 cee 1 : 5 103 | 77.50, 90.19 lf12 July 22, p.m........- do.....----| 4)---|.-.f.--- () {39 | 1 3) 4) 98 | 66 | 0.26 SR ile We TOE cee a wn do... <) fre pe | 2¢' 1° ie eae She nes ei | 2| 1 ‘ 103 | 79 | 90.27 July 24,a.m....|..... do... ae ee giro] 19)...)...1...1 1) 4} 5) 103 | 79 | 90.28 (SE ee Pea do... ieee wis UE areal ..--laltg | 3! 0 3} 103 | 79 | 90.21 eee aes do... Pe, ale Bae ic See be he Oa 1 0} 1) 103.5 79 | 91.04 oe ee do 7 Eel Toe & of--f-2) 2] 2] 3} 103.5] 79 | 96.38 Aug. 2,a.M..... Rabbit........ 1 (ME see “15h Sill GEG, SE oo) th alee 0 1) 1) 103.5, 79 | 91.00 Aug. 3,a.m..... Goines ple ri hel FA Se OES ae ae ?| 2] 1) 103.5) 79 | 90.96 Se ee ae oe ee Ge ee ee ee Se 2} 0} 2) 104.5, 79 | 92.32 Aug. 10, a.m....| Rabbit........ | 2 --2d a zee 2 0 | 104.5, 7 | 92. 32 a es aig 3} Id es sat) FED ts 10} 104.5 7 : Aug. 10, p. m do ne 7 ig a | | | ‘ 6 57 | 92. 38 Aug. ll,a.m....|..... do | 4 PA SF | 1] 1d (93! 19|...|...]... 31 3] 6 pee 73 | 91.32 Aug. 11,m.noon.|.....do.........| 71d... -y Neg ) aiid 3) 2 5| 104.5) 79 | 92.44 Bs| 1g] 1¢ a 58 Aug. oS es ee ee 13. --|19 29 29 1g he ae ae cs 6 6 12 104.5 79 92. 13 | 1g shol... ; ; ee ee ae | 12191... tighes 439 ig|19}...|... ‘ 5 9] 104.5| 80 | 91.96 t ' Aug. 12, p.m | do ae ee Be ee ghee u 19 A i : 4 6| 104.5] 73 | 90.53 Aug are oe do. dle abe. dees Me ite! ait | 1 1) 2) 104.5) 73 | 90.15 Aug. 13, p.m....|.....do. ~ cy 19] 32 eS jon et ey 4) 1 5| 104.5] 73 | 90.15 Aug. 15,a.m....|..... a ae Ses gh rs ae aL 8 2} 0, 2| 104.5) 73 | 89.67 Total....| 103 -.-|.-- ----|oee| neal feo a. YY 2 es eee eee iy | | i
1 The ticks which molted on this date are included with those recorded on the following day.
In August, 1910, at a daily mean temperature of from 91.96° to 92.44° F. molting commenced on the thirteenth day. The longest period from dropping to molting was 22 days. This occurred at a daily mean temperature of 69.36° F. The males and females began to appear about the same number of days after dropping. The weighted average molting period of 42 nymphs which transformed to males was 15.89 days. In the case of 40 females this average was 16.22 days. The weighted average period from dropping to molting for all nymphs observed was 15.62 days. A total effective tempera- ture of 636.5° F. seems to be required for this transformation.
The adult (Tables LX XXVITI-LXXXTX).—The number of males and females which molted from nymphs was practically equal. The greatest longevity which has been observed was 359 days. This record was made on a lot of 29 males and 29 females which molted from nymphs August 10, 1910. The last male in this lot died May 31, 1911. It had lived 294 days. The females appear to have a slightly greater longevity than do the males; this is particularly noticeable
188 LIFE HISTORY OF NORTH AMERICAN TICKS.
among those ticks which have once been attached to a host in the adult stage. Hot weather also appears materially to shorten the longevity of both sexes.
TaBLE LXXXVIII.—Longevity of adults of Dermacentor occidentalis.
Number. Date molted or collected. a a All dead. meet Male. Female. 1910. Days.
Molted: Sully 422-2 coset eee eee ee 0 INO Cts IS=NOVve125511 91 One eee nena 106-147 Moltedi Aug slOSs 2 5 ease eee 29 ZO ACO AMOI 5. ce satinc eee eee 359 Molteds Aug a 2 -e scene ee 1) eee te May 275 Lois i ue seee oe is epee ees 285 Molted {Agi e5 15-20 ac ae ee 2 2 Mary SiO Inf ee ae a ee 266 IMolted GA ie en aera eee 0 1 | Nov. 38-Dec. 20 -EOLO baa SAE oe 103-125 Molted, YATE IOY: Van tee ely SE OS eS 2 OM May: 205191 S225 Jyokee as ee eee 269 Collected, PA DESO. ca pee ee ms 0 1| July 19-Aug. LS NOI: Mae Re ect eee 118-147
DOs ee Ns oe ee eo ee 1 1G | DUNC h OO RS eae ene 66 Collected WAwrsbee ena. 552 e se see 2 8 | Aug. 18-31, LOL OE Rear ee ee a es A ee 135-148 Collected, WASP TNS Be meses Bene 8 4] June 18-July LS 1 O1Qe= eee oe eee 71-101 Collected, 21ND) C77 ENS ie ge RN Tes 0 Syleouly WSS Anie Ss 1O1ORN a ee soe eeee 82-113 Collected, May 28) ek. Se i ee 0 2 BONS 2c ee ES ai Pare ey eee ee 51-82 Collected, OCT AIER SBe eet ners 6 5 Apr. Op OUTS 2 CRANE ee oe oe ee 166 Collected; OCES26) eth ee ee cone Aa 0 1} Mar. 20, DR Ee es Aaa gs Deh era and = 145
Copulation of this species has not been observed before attaching to a host. Mating has been seen to take place upon bovine hosts any time between one and several days after attachment. In one case a female became fully one-half engorged before she was visited by a male. One female which was not observed to be fertilized became nearly engorged and dropped in about the normal engorge- ment period. However, no eggs were deposited by this individual.
Taste LXXXIX.—Engorgement of adults of Dermacentor occidentalis on bovines.
Females dropped engorged—days
following attachment. Date females |Num-| State of en- State of en- applied. ber. | gorgement. Date attached. Total gorgement. 2|41!]6 | 71] 9 j10 |17 | number dropped. 1910. 1910. A rs Oase seu On Slehtlyy. ton WA prs O bea aeee oes aee Wels LS ae ears dna 1} Fully. one-fifth 7X50) OR ee eee 2) | Winengorged:|| Apres 22) - 32554 eens ee Seal al 1 | Two-thirds. Maryi9\s os so 8a ee 10 | Unengorged | May 9........- Ail | eee oe nian) A 5 | O n e-fourth to one- to two- eighth. thirds. May20b asso tj eUnengorgveds| May; 20 sprees || ee |e lene |e 1 | One-half. dUNe 4 See ee 3 | Slightly. -..- June Ass oye eae rele es eae 1 | Two-thirds. Junew4as.. 232552: ile OO aes: June 15. el Fee esl eal baal ee 1 Do. Aug. 26-31 ......- 8 Unengorged. Aug. 31- Sept. Te rs eae ee Ee Pa 2| Fully. Septe22)<- sesso YES oe do......| Sept. 24 - ee (eres ested esa ea 1 | One-eighth.
Males have been observed to remain upon a host for 31 days. Females which had become one-fifth engorged upon one host were found to attach to another host when given an opportunity. In most cases ticks applied to a bovine attached within less than one day thereafter, but in a few instances both males and females were
THE PACIFIC COAST TICK. 189
found to remain unattached for 4 or 5 days, some of these dying in the meantime. The females which became detached before becom- ing fully engorged, as indicated in Table LX XXIX, were undoubt- edly dislodged by the rubbing of the host. The shortest period in which females were known to become fully engorged was 6 days; the longest period was 17 days. In the last instance the female was only two-thirds engorged when she was detached.
LIFE CYCLE.
A period of at least 105 days elapsed between the beginning of hatching of the eggs deposited by a female and the death of the last larva. The larve may engorge in 3 days after attachment and in summer molt as soon as 6 days after dropping. The transformation from larve to nymphs requires a total effective temperature of 263° F. Nymphs may live at least as long as 76 days during cool weather; they engorge as soon as 4 days after attachment and may molt as soon as 13 days after dropping. The molting period for nymphs which become males and those which become females is practically the same. A total effective temperature of 636° F. is required to pro- duce this molt. Adults may live as long as 359 days. Females may engorge in 6 days, commence depositing in 4 days after dropping, and deposit as many as 4,555 eggs. The eggs hatch as soon as 21 days after deposition and appear to require a total effective tempera- ture of about 842° F. for incubation.
This tick has been found to occur in nature at all seasons of the year. The adults appear to become most numerous during the rainy season. Many engorged females are to be found on hosts during December.
ECONOMIC IMPORTANCE.
Owing to the fact that this tick frequently attacks man and often occurs in great abundance on domestic live stock, it is of considerable economic importance in California and Oregon. Its presence through- out the entire season in greater or less numbers also increases its importance. Where it occurs it is usually spoken of as the ‘‘wood tick.”” In central and western California and western Oregon it is the most common tick which attacks man. A number of cases have been brought to our attention where the bite of this tick has caused considerable local inflammation which, in some cases, has required a physician’s attention. It is quite common for the rostrum to be broken off when the ticks are removed and in such eases the irrita- tion and itching usually persists for several weeks.
Although numerous authors have used the name Dermacentor occidentalis in connection with Rocky Mountain spotted fever, it is doubtful if this species is concerned in the transmission
190 LIFE HISTORY OF NORTH AMERICAN TICKS.
of that disease. The use of the name was due to confusion regarding the identity of the tick Dermacentor venustus, which is the known transmitter of this disease in nature.
NATURAL CONTROL.
No natural enemies of this species have been observed by the writers. However, it is probably subject to the attack of the various predaceous enemies of other tick species. McAtee (1911a) states that ticks of this species have been found to be eaten by the dwarf hermit thrush (Hylocichla guttata nana).
ARTIFICIAL CONTROL.
The comparatively short longevity of the larve and nymphs of this species indicates that it may be possible to practice the rotation method of eradication. This method appears to be more promising than the use of dips on account of the fact that the engorgement period of the immature stages is quite short and usually takes place on small wild mammals. The occurrence of the species throughout the year is also an obstacle to the practice of dipping or mopping animals with tickicides.
THE AMERICAN DOG TICK. Dermacentor variabilis (Say).
The common name of this tick is given it because in this country it is the most widely distributed species which commonly attacks the dog.
DESCRIPTIVE.
Adult (Pl. XV, figs. 5-11).—Males from 3.5 by 2.5 to 4.5 by 2.5 mm. Females, unengorged, about 3.75 by 2.25 mm.; engorged, 10 by 7 by 5 to 15.5 by 11.2 by 7.4mm. Male reddish brown, dorsum with irreg- ular white marks; female reddish brown, scutum with a white band on the lateral margin, broadening posteriorly; a brown marginal stripe near each eye and sometimes two white median stripes.
Nymph (Pl. XV, figs. 2-4)—Unengorged, about 1.5 by 1 mm.; engorged, 3.5 by 2 by 1mm. to 4.by 3 by 2 mm.; average 3.5 by 2.5 by 1.5 mm. Color, unengorged, pale yellowish brown; posterior margin of scutum dark brown, lateral margins of scutum with brick- red markings; in living specimens the intestines are visible as brown bands through the body walls; engorged, slate-gray. Capitulum 0.287 mm. long (from tip of palpi to base of emargination of scutum); scutum 0.488 mm. long by 0.526 mm. wide.
Larva (Pl. XV, fig. 1)—Unengorged, about 0.60 by 0.35 mm.; engorged, 1.5 by 1mm. Color, unengorged, pale yellow; lateral margins of scutum brick-red; engorged, dull gray. Capitulum 0.17
THE AMERICAN DOG TICK. 191
mm. long (from tip of palpi to base of emargination of scutum); scutum 0.255 mm. long by 0.32 mm. wide.
Egg.—Ellipsoidal, pale yellowish brown, shining, smooth. The average size of those measured was 0.527 by 0.379 mm.
HOST RELATIONSHIP.
The host of the type is not recorded. The dog is the most common host of the adult stage of this species. Out of 112 lots collected by agents of the bureau the following numbers of lots were taken on the different hosts listed: Dog 62, fox squirrel 9, raccoon 6, opossum 6, ox 5, badger 3, coyote 3, skunk 3, deer 2, man 2, wolf 2, ass 1, Mexi- can lion (Felis hippolestes aztecus) 1, fox 1, hog 1, horse 1, rabbit 1, weasel 1, wild cat 1. The lot from the Mexican lion, consisting of 9 males and 3 females, was collected by Mr. D. K. McMillan at Ray- mondville, Tex., November 20, 1910.
‘No larve known to be of this species have been collected, but a considerable number of nymphs have been taken on fox squirrels and one lot was collected on a swamp rabbit (Lepus aquaticus). Adults of both sexes were taken on the fox squirrels along with the nymphs. Most of the lots collected on this host were taken by Mr. J. D. Mitchell in March and April, 1909. In rearing experiments larve attached to a bovine, but failed to attach to dogs, even after several attempts were made.
GEOGRAPHICAL DISTRIBUTION.
(Fig. 16.)
The locality from which the type was described is not recorded.
The determination of the distribution of this species is complicated through questionable identification due to the fact that, superfi- cially, it closely resembles several other species.
The species is common throughout the eastern half of the United States. It is recorded from Alaska, Labrador, Ontario, and Nova Scotia on the north and its range extends southward through the United States to the Gulf coast. There is also one record from Mexico. Although the species has been listed from Colorado, New Mexico, and Arizona, our investigations indicate that it does not nor- mally occur in those States. There is, however, a considerable area in western California and southwestern Oregon where the species is very common. In this region and in the Central and Southern States the species appears to occur most abundantly.
LIFE HISTORY.
Observations on the biology of this tick have been published by Morgan (1899, pp. 133, 135), Hunter and Hooker (1907, pp. 50-51), and by Hooker (1908, p. 47).
192 LIFE HISTORY OF NORTH AMERICAN TICKS.
The egg (Table XC).—The minimum preoyviposition period for a large number of ticks observed at different times of the year was 5 days and the maximum 14 days. This minimum preoviposition period was observed in a number of instances during the summer
months, while the maximum period was recerded once in March and once in April, 1909. The mean temperature during the shortest period was 80° F. The period of oviposition varied from 14 to 29 days with an average of 22.3 days. A tick which was collected on a
Bul. 106, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE XV.
Fig. 1.—Unengorged larva. Fig. 2.—Unengorged nymph (balsam mount). Fig. 3.—Engorged nymph about to molt to female. Fig. 4—Engorged nymph about to molt to male. Fig. 5.—Male, dorsal view (Texas form). Fig. 6.—Unengorged female, dorsal view. Fig. 7—Male, dorsal view (Oregon form). Fig. 8—Unengorged female, ventral view. Fig. 9.—Male, ventral view. Fig. 10.—En- gorged female, dorsal view. Fig. 11.—Engorged female, ventral view. (Original.)
fe Wop yew't
THE AMERICAN DOG TICK. 193
dog August 10, 1909, measured 15.5 by 11.2 by 74 mm. It began depositing on the sixth day and continued depositing for 23 days, during which time 6,855 eggs were deposited. This is the maxi- mum number of eggs recorded by us for the species, but Prof. H. A. Morgan (1899) has recorded 7,378 as being deposited by one tick between May 8 and June 26. The minimum number of eggs depos- ited by 11 ticks was 2,808, the average 4,568.
The minimum incubation period for eggs kept in tubes out of doors was 24 days. This record was made on eggs deposited August 17, 1907. Eggs kept in the laboratory at a mean temperature of 84° F. hatched in 20 days. An effective temperature of at least 825° F. appears to be required for their incubation.
TaBLeE XC.—IJncubation and longevity of larve of Dermacentor variabilis.
IN LABORATORY.
Temperature during in- cubation.
Larval
Eggs Hatching All larvee dead lon- depos began J : } a sa gevity- |raxi-| Mini- pe, otal
mum./mum.| daily eek
ean| ive
1908. Days. | °F.| °F. | °F. | °F. Ce Oe Cee ae fee 86 47 | 70.41)1,041.50 Jone 4... ....} June 28. ....- Ue A Se ee 98} 91.5) 69 | 80.98) 949.50 perry er Sy ce =. Sh Se as See ee ee 95, 91 69 | 80.33} 895.75 sumo tc...) saly 24... - ON ae se ee ee §2; 93 70. 5} 81.31}1, 264. 25
ee ee Ter EY 2. Dg y Ro eS ee eee ae 296} 95 70. 5] 83.26] 888
1) OA Uae (Bis gi-7 ee ame Pre AL | eee. See eee 318} 95 74 | 83.86} 899 2 SA eee BA Ce St TE Be Op ee ee 335} 95 7 83.98] 860.50 aes =...) July 30. . 2<.. Apr. 16-May 7, 1909. .........- 260-281} 95 74 | 84.26) 825.25
Ei Fae eS Vwi f 35 Oe Ngw25-16: 1908! — 8 ee 100-107} 95 7 84. 29 7
July 15....... myi oe... 277-284] 95 | 76.5] 85 | 882 Ug’ UT SV 1 a ee ae 308} 95 76 | 85.18) 886.75 Aug. 16,1909 Jan. 28—Feb. 25, 1910........-- 142-170; 110 77 | 89.391,112.75
Apr. 25,1910 July 19-Aug. 4, 1910........-.-- 49-65) 93 43 | 73.89)1,143 May 7,1910 (I |) ee ee ee eee 282) 100 59 | 76.62)1, 042.25
May 9,1910 July 19-Aug. 4, 1910.........-- 41-57| 100 | 59 | 77.42/1,067 May 17,1910 Wels. MEUM eee oe ee | 239) 100 | 60 | 79. 30) “943.80
i OUT OF DOORS.
Apr. 13,1906 | May 25,1906 3 OR oe ae Se be os 73 1,106
ay 5,1906| June 8, 1906 “- SEES A PS FP 2.941, 048
June 25,1907 | July 21,1907 7 CRG ig ae SE RS Be NE Se Cea .5} 81.301, 034 Aug. 17,1908 | Sept. 9,1908 Pe ae ee ee ; 85) 908. 40 June ?,1910] July 9,1910].-...-- Cee 2 ee eT pe ee eg eed ae See ea (em eee Aug. 9,1910} Sept. 4,1910 By a a ee . 491,174.25
Aug. 11,1910 |..... py 72) |e aif NR ear SRT 4 Roary hahs eee .5 ‘seve
The larva (Tables XC-XCII).—The greatest longevity of the larve of this species recorded by us was 335 days. This lot of larve hatched out June 27, 1908, and was kept in a glass tube on moist sand in the laboratory. One lot of larve kept in a tube out of doors lived 262 days. The incubation and larval longevity records given in Table XC are a few from a large number of records selected to illustrate the variation in these developmental periods. As may be
21448°—Bull. 106—12——138
194 LIFE HISTORY OF NORTH AMERICAN TICKS.
seen in the table, the longevity of the different lots varies greatly. We have not been able to account satisfactorily for the large differ- ences in lots kept under similar conditions.
The shortest time in which engorgement took place was 4 days, the greatest number dropping from the host on the fourth to sixth days, while the last to leave the host dropped on the seventh day.
TaBLeE XCI.—Engorgement of larve of Dermacentor variabilis.
Larve dropped engorged—days following application. Total
Date larve applied. Host. number
dropped.
DULY pol AGO oe seek ee ee cee ea eee Boyine....
0 0 0 3 3 0 0 6 Aug. 5; 19076 seates. See ace eGEke J4 GOse2 ve 0 0 0 37 27 2% 0 66 TUNE 5-1 GUSH aes cede se ome er ae eed Onssase 0 0 0} 5 17 24 3 49 pA gS 1908 Me eel cccee me soceseeee & 2 GO yaaa 0 0 0 0 0 5 0 5
Molting occurred in August as soon as the seventh day after drop- ping. At amean temperature of 81° F. molting took place in 8 days, during which time a total of 306° F. of effective temperature accumulated.
TaBLeE XCIT.— Molting of engorged larvx of Dermacentor variabilis.
Engorged larve molted— Temperature from days following drop- dropping ns date first ing. ¢ ping Total tick molte Date engorged larvee dropped.| Host. : | Bee B molted : |) EVER 5 F mum. | mum. | daily mean. a pe ae ii oO At pVA MOOT Ss cto see = dee Somes Bovines.|) (3) (ONO As aie) IO 2 dl Ree ae Meee solo occ ac Wags '5, 1907S. Se Reale dOno=s Se Oa 2a, ACTON MOR Stii.i..colls 2 eee | ee TE 17 le en ee wi do: 87 |. 9) 1821 te) OLE sou 8 OR |e!) en AE. LOO fcc cao aso ce reel ooe d02..2. 20. |) Aalde eeeelsnte clatter 2a lien nee n|tson eee acer Sept WOO wes tennessee Dogs see ARs OF MOA MOS O4). a0 0 floor See Jurie'9;, 908 64. en 2 science Bovine:-| cov) O00) 925) 20) S00 4 91.5 69 79. 87 SUNT OIGOSE eee ea ee ene dors--- TST ON On Sel ras ea 16 91.5 69 80. 50 June G082 ce aa es - Se seal oe doses. ZAM HOR 23a) eee oul ya vata 14 91.5 70 81.19 June d2: 1908= 3. 4-32 -oe--e 5c Orne. 33) Ol sa} MOM Only (One 2 91.5 71.5 81.39 Agi 2419085 pe see sae ceee se elec do=2te- Be oe On| el ON || eae erect 5 90 75.5 83. 27 Motal’ one edie os 100 | ie MD ra
The nymph (Tables XCIII-XCIV):—A number of nymphs which molted on August 18, 1907, were alive March 5, 1908, but dead on March 21, 1908, the longevity of this lot being from 7 to 8 months. In another instance, however, nymphs which molted on June 18, 1908, were dead on August 4 of that year, and the last individuals of a third lot, which molted September 9, 1908, died between October 16 and October 26 of the same year. All of these lots were kept on moist sand in the laboratory.
THE AMERICAN DOG TICK. 195
The shortest period of engorgement recorded in our observations was 4 days. The last nymph to drop left the host on the eighth day.
TaBLE XCIII.—Engorgement of nymphs of Dermacentor variabilis.
Nymphs dropped engorged—days following
application. Total Date nymphs applied. Host. number | dropped 1 2 3 | 4 5 6 | 7 SS ii? ihn Soy i i a a as red ee ee Re I Oe Bovine....| 0 0 0 iy ee 1 1 1 | 5 Oss at a TAT i ae 0 0 0 4 | 1 0 0 0 5
Engorged nymphs which dropped September 1 commenced to molt on the seventeenth day. One nymph which dropped August 28, 1909, molted on the sixteenth day after dropping. During this period the maximum temperature was 101° F., the minimum 78.5° F., © the average daily mean 89.3° F., and the total effective temperature 740.8° F.
TaBLE XCIV.— Molting of engorged nymphs of Dermacentor variabilis.
Engorged nymphs molted—days following dropping. s Number molted.
Date engorged nymphs Host.
ropped.
| 16] 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 3
2 -|3 =
s|2| 3
Zz Sile| « 0 ae |) Rabbit l... 2) of of o| of oO} o| Oo 0 o}19]....] 1 1+ Bont. 10.) 85.2.2 Bovine.... 5} OIF 1d) 19} 29] OF OF O OF O 2 3 5 LS) Ses ie 2] d1s}1g} 0} Of Of O OF OF O 2 0 2 ee | ee Bess. 1] Of 0/19] Of OF Of O O OF O 9 1 1 Sant. 4 1007.22 | ae 1} oF O19] of Of Of OF OF Oo] O OF 1 1 Aug. 28, 1909...........- Squirrel... 119] Of 0 of 8 O OF OF OF O O 1 1
PS Gere ar eee | fae, es OD |---| OS ae aa) ust
1 Collected from a swamp rabbit.
The adult (Table XCV).—The maximum adult longevity observed by us was 233 days. This record was made on a single female which became adult September 13, 1909. A female which was collected on an opossum May 10, 1910, lived 202 days, and one male in a lot con- sisting of 2 males and 3 females, which were collected on a squirrel April 6, lived 106 days. Other lots of collected individuals lived from 15 to 93 days. If a large number of freshly molted individuals were kept for longevity tests without allowing them to feed it is probable that some individuals would be found to live longer than any observed by us.
In our observations mating has been preceded by a period of feed-
ing of from 3 or 4 to 10 or more days after attaching to a host and \
196 LIFE HISTORY OF NORTH AMERICAN TICKS,
has continued for a day or so only. Females have been found to reattach even when engorged to a considerable extent. Unengorged females taken from dogs to which they had attached, and on which they had probably mated, engorged as soon as 5 days. Nine days was the shortest period in which previously unattached females engorged. Morgan, however, states that females engorge in from 5 to 8 days.
During engorgement the females constantly excrete what appears to be undigested blood. The adults also void considerable excre- ment soon after molting from nymphs.
A male which, with a female, was placed upon an ox November 1, 1907, remained upon the host, frequency changing its position, al eerie 14, when it was fn attached but dead. Thus it remained _ upon the host for 105 days from its attachment and 91 days after the female had dropped engorged. Other males have disappeared from the host on the eighth day after the females dropped.
TABLE XCV.—Engorgement of females of Dermacentor variabilis.
Females Period Adults applied. Host. dropped of attach- Size engorged. engorged. ment. Days INO Vice O07 se sedece case poe a aes an NS el INGVe Woes ee 14 | 13 by 9 by 5mm. Mar. 23, 1908s Ss. ec Boh eSe dO eke ae ee Pecos ee 9|12by 9 by 5mm. June 19, LOOSE LE So sees ovine (reattached)...) June 24 5 | 13 by 11 by 7 mm. Fai diwis Sieiwinie se spite! sere ae OSe a morats aateitalcicete une 25 6 | 13 by 11 by 7.5mm 12 by 9 by 6.5 mm 12.5 by 9.5 by 8mm. IDO Sean h oreseasenes| steed dOsc22. 5 aasceckeeee June 26 (5).... 7 \413 by 10 by 8 mm. 13 by 9 by 7 ae 13 by 10 by 7 DOs eh cae aee eee Bovine: =..°. 36 -4e ee Jane 2ees sce 8 12.5 by 10 by 7.5 mm, Aug. 24, 1908 (slightly Borie (reattached)...| Aug. 30....... 6} 12 by 7 by — mm. engorged). Ang: 2419088 22 5 Se ee GOss Re Ss ee ares AUG. Obs. Sse 7| 10by 7 by 5mm. Apr. LOM90O Ss oe noe: gee Gone: ae ADE: Zi ss csoees 8 | 13.8 by 9.4 by 7.3 mm. Sept. Ss: ggg = be Bac eee dot. 2h Seo Se ey Sept. 16s-5225 8 | Fully engorged. be rs See ee | eae Co Coie eee ra eer ISIE 0 re Gy me te 9 | Partly engorged. Mar. 36, 1910... Re (es Fe MOS wet os HX) 0) 5g 1 Fees are 16 | One-third engorged.
LIFE CYCLE.
Larve may live for 335 days; they may engorge as soon as 4 days after application to a host and molt as soon as 7 days after dropping, a total effective temperature of 306° F. being required for molting. Nymphs may live for from 7 to 8 months; they engorge as soon as 4 days after attachment and may molt as soon as 16 days after dropping. A total effective temperature of about 741° F. appears to be required for this transformation. Adults may live as long as 233 days; they may engorge in 8 days (5 days ?) and commence ovipositing as soon as 5 days after dropping. As many as 7,378 eggs may be deposited. Embryonic development may be com- pleted in 20 days, a total effective temperature of 825° F. being required.
THE TROPICAL HORSE TICK. 197
Adults of this tick have been collected on animals in Texas at all times of the year. However, they appear to be most abundant in the spring and early summer. Nymphs have been collected on animals in considerable numbers in February, March, and April, and in one instance in August. With little doubt the immature stages are to be found on hosts nearly all the year round.
ECONOMIC IMPORTANCE.
Aside from the fact that this species occasionally attaches to man and domestic animals and often causes considerable annoy- ance, it is of no economic importance. The ticks are easily removed from a host and their attachment has not been known to produce any serious consequences.
NATURAL CONTROL.
The many bird and other enemies of the cattle tick undoubtedly prey upon this tick also. Dogs have been observed by us to crush them with the teeth, both when attaching and after dropping.
ARTIFICIAL CONTROL.
This species has not been found to occur in numbers except upon the dog and some wild mammals. When dogs become badly infested _the ticks may be removed by washing the dogs with one of the standard tick dips. Ordinarily hand picking will suffice to keep them in check.
THE TROPICAL HORSE TICK. Dermacentor nitens Neumann.
The common name of this species is derived from the fact that its distribution is restricted almost entirely to the Tropical Life Zone and that the horse is its principal host.
DESCRIPTIVE.
Adult (Pl. XIII, figs. 8-10, 13, 14).—Males 2.5 by 2 mm. to 3 by 2mm. Females, unengorged, 3.25 by 1.75 mm. to 3.5 by 2 mm.; engorged, 9 by 7 mm. to 12 by 9 by 5mm. _ Both sexes are reddish brown and without white markings.
Nymph (Pl. XIII, figs. 7, 11, 12).—Unengorged, about 1.33 by 0.9mm.; engorged, 2.9 by 1.8 by 1mm. to 3.5 by 2.2 by 1.3mm. Color, unengorged, pale brownish yellow; engorged, dark gray. Capitu- lum, 0.359 mm. long (from tip of hypostome to base of emargination of scutum); scutum 0.54 mm. long by 0.641 mm. wide. The shape of the nymph, particularly when engorged, as with the engorged female, is quite typical of the species; the greatest width is at the
198 LIFE HISTORY OF NORTH AMERICAN TICKS.
third pair of legs, from which the body is very noticeably constricted posteriorly.
Larva (Pl. XIII, fig. 6).—Unengorged (in balsam), 0.714 by 0.470 mm.; engorged, 1.5 by 0.9 by 0.6 mm. Color, unengorged, yellowish brown; engorged, steel-gray. Capitulum 0.205 mm. long (from tip of hypostome to base of emargination of scutum); scutum 0.290 mm. long by 0.372 mm. wide.
Egg.—The average size of 10 eggs measured was 0.565 by 0.419 mm. Color yellowish brown to brown; shining, smooth.
HOST RELATIONSHIP.
The type host of this tick, the horse, is the principal host for the species. This tick has also been taken from the ears of the mule at Brownsville, Tex., and at Tampico and Victoria, Mexico, Bishopp found it commonly in the ears of both the mule and the ass. It prefers the inside of the ears as a place for attachment. Hooker has found a number of specimens attached in the horse’s mane between the ears and several to the belly. This, however, was due to the fact that the ears were literally filled with ticks so that there was no place in the ears to which they could attach. In Texas several larve have been taken from the ear of a goat. The tick has also been taken from the ears of the ox and of a calf. A single specimen in poor condition, but apparently of this species, was taken at Kerr- ville, Tex., by Mr. F. C. Pratt from a deer skin that had been’ removed in January. In our studies we have found them to attach to the scrotum of a bovine and develop to engorged adults.
GEOGRAPHICAL DISTRIBUTION. (Fig. 17.)
Jamaica and Santo Domingo are the type localities for this species. In the vicinity of Brownsville, Tex., it is an important pest to horses which run in pastures; it has also been taken at Harlingen and at Corpus Christi, Tex. A single specimen which appears to be this species was collected at Kerrville, Tex., but the species has not been found during subsequent collections in that vicinity. There seems to be much doubt of the correctness of the record of this species from Arizona. The tick was found in abundance at Victoria and . Tampico, Mexico, but careful search for the species failed to reveal its presence on the plateau in the central and northern parts of that country. It has been recorded from Guatemala, Panama, and Costa Rica in Central America and from Cuba, Jamaica, Haiti, Santo Domingo, and Trinidad in the West Indies. It appears to be a serious pest in Cuba and Jamaica.
THE TROPICAL HORSE TICK. 199
LIFE HISTORY.
Observations on the biology of this species have been published by Hooker (1908) and by Newstead (1909). The egg (Table XCVI).—The first 3 ticks the oviposition of which
was recorded were collected from the ears of a horse; the next 7 were
Fic. 17.—The tropical horse tick, Dermacentor nitens: Distribution in North America and West Indies. The large dots show localities where the species has been collected in our investigation. The small dots indicate the probable range of the species in North America and the West Indies.
picked from the ear of a mule; and the last 2 dropped from the ear
of a bovine.
The preoviposition period in the 12 ticks recorded varied from 3 to
15 days. The minimum period occurred in the case of 2 females
2°00 LIFE HISTORY OF NORTH AMERICAN TICKS.
which dropped from a host on July 27. These ticks were kept at a mean temperature of 85.4° F. The period of deposition ranged from 15 to 37 days. The length of this period, as well as that of the preovi- position period, is materially affected by temperature, the high tem- peratures producing the shortest periods. The maximum number of eges deposited by 1 tick was 3,392 in the lot of 12 females observed; the average was 2,784.
The minimum incubation period for eggs in the laboratory at a mean temperature of 85° F. was 24 days. An effective temperature of 935° F. appears to be required for incubation.
TaBLE XCVI.—Preoviposition, incubation, and larval longevity of Dermacentor nitens.
OUT OF DOORS.
Temperature during incubation.
Date ae 5 engorged| Eggs |Hatching ee i Bees pein l deere OUSTEET | T0252 period. dead. | gevity. | Maxi- | Mini- pies com
aes aber mean. tive
1908. 1908. 1908 Days. 1908 Days. pels uae eH eae Apr. 22| Apr. 29| June 5 38 | Aug. 15 71 91 43 73.2 | 1,149.2
DOW | i. dolce June 6 39 | Aug. 7 62 91 43 73.5 | 1,187.7 May 17| May 21 | June 20 31 | Aug. 14 55 93 62 79. 3°) 1,125.3 May 18| May 26 | June 24 30 | Aug. 15 52 96 62 80.4 | 1,120.6 May 19 doesce - June 26 32 O22 50 96 62 80.3 | 1,195 May 20| May 27 | June 28 33 | Aug. 19 52 96 62 80.3 | 1,232.5 May 22| May 26 |...do..... 34 | Aug. 28 61 96 62 80.3 | 1,268.2 May 26} June 2] July 1 30 | Aug. 29 59 9657 62 80.5 | 1,124.9
IN THE LABORATORY. a A May 2) June 1 Bille Lv eee eae, ts Seek ees oe 87 56 toe 999 satewio ss May 3) June 3 Oke pees een eee ce oe 88 56 75.8 | 1,049.5 AMS arse May 9j| June 5 DR | Wee cna Sela ee aes 88.5 65 77.5 966 ee ee May i0| June 6 DA Sak Se eee | ie igaee 88.5 65 77.8 957 Es eee May 13] June 8 PAB) Sosa renee SM Oe pa te ar 90 65 78.3 952.8 op. © pple May 14]| June 9 7 fa | eee? eh ea Pe aes ee ey 90 65 78.7 963.3 ye A eee Maye 5) edoees- AG yi al ee Ne ea 90 67 79 935.3 ay Le ae July 31 | Before essithan'30 | Decs ui -Abouti98)|S-e 22-0 52|o- 42 eases) aceemse ae oe eee Aug. 29 Amare Auge, 22-20). 231 bess than 28" Nove 26) |PAIDOUT SO) Saas e eee eet aera | sate see ae Saeaice ores Aug. 6] Aug. 29 24 | Nov. 26-| 89-117 99 73 85.25 | 1,014 Dec. 24 ee Ang. 9 | Sept. £ 24| Oct. 26-| 55-77 96.5 73 84.4 | 1,000 Nov. 17
The larva (Tables XCVI-XCVIT) .—As is shown in Table XCVI, the longevity of larve which hatched in June and were kept in tubes under the most favorable conditions was only 71 days. All of the larve from eggs of females which dropped in May were dead 2 months after hatching. Seed ticks hatching from eggs isolated at daily intervals and kept in tubes in the laboratory were frequently found to die in 10 days or 2 weeks. The greatest longevity of this stage observed by us was between 89 and 117 days. This species, the cattle tick, and another species of Dermacentor (albipictus), which is now being studied, are the only species occurring in the United States, which, so far as known, pass both molts upon the host. As a
THE TROPICAL HORSE TICK. 201
result of this habit great numbers of ticks reach maturity and repro- duce, but fortunately there has also resulted a great decrease in the power of the larve to withstand periods of fasting.
As is shown in Table XCVII, larve may engorge and molt as soon as the eighth day after attaching to a host. The longest period from larval attachment to molting was 16 days.
The nymph (Table XCVII).—In two of the three lots recorded in Table XCVII nymphs became engorged and began molting on the seventeenth day after being applied to the host as larve. In the third infestation nymphs began molting to adults on the twenty- fourth day after being applied. The period from the molting of the first larvee to the molting of the first nymph was 8 days in one instance and 9 days in the other two cases observed. In one instance the nymphal period appeared to have been only 7 days.
The adult (Table XCVII.—The mating of males and females of this species, which molted on the host on the same day, took place as soon as the second day following and was continued until the engorged females dropped. This habit appears to be similar to that of JJar- garopus annulatus. A male Amblyomma americanum has been found attached beneath a female of this species, the ventral surfaces being in apposition as though in copulation. The sexes remained in this relation for only a short period. Likewise males of Jlargaropus annulatus australis and Dermacentor variabilis have remained mated with females of the tropical horse tick for a number of days. Several females have engorged and dropped, apparently without having been fertilized. One unfertilized female remained attached from the time it molted on May 6 until May 26, when it dropped unengorged. A second unfertilized female which molted July 18 dropped August 11 when only slightly engorged.
Females have engorged as soon as 9 days after molting or 26 days after attachment to the host as larve. The longest engorgement period observed was 23 days after molting, or 41 days after being applied to the host as a larva. Females collected at Brownsville, Tex., in November have reattached to a host 3 days later. A slightly engorged female thus transported attached and dropped engorged 7 days later, measuring 10 by 8 by 5 mm. Newly molted females reared from engorged nymphs taken from a horse have attached to a bovine. One thus attached on December 9, 1907, dropped en- gorged 11 days later, measuring 10 by 7 by 4.5 mm. A second, attached at the same time, dropped after 15 days of attachment, measuring 10.5 by 7.5 by 4.5 mm.
A male has been found to remain upon a host 84 days after the first female dropped, or 99 days after attachment as a larva. At the end of this period it was found dead in the retaining bag. Upon another host a male remained for 72 days after the last female dropped, or 86
202 LIFE HISTORY OF NORTH AMERICAN TICKS.
days after it had been collected from an equine and placed upon the bovine. It detached and escaped from the bag at the end of this time.
A peculiar habit which is especially noticeable in this species is that of the excretion, by the female during engorgement, of large quantities of a substance which when dry resembles coagulated blood. This habit, while particularly noticeable in the members of the genus Dermacentor, is most pronounced in this species. It is a frequent occurrence for the male to get incrusted in the excreta and, being unable to extricate himself, to perish. It is this habit of voiding large quantities of excrement that increases to some extent the economic importance of this tick.
PARASITIC PERIOD.
The parasitic cycle of three lots was followed upon bovines at the laboratory. Two of these lots were placed upon the scrotum of the host and the third in the ear.
On April 10, 1908, numerous larve were placed on the scrotum of a bull; 2 molted to nymphs on April 23, 2 on April 24, and 1 on April 25, or the thirteenth, fourteenth, and fifteenth days, respectively, after application. On May 4, 1 molted to afemale; May 6, 1 molted to a female; and May 19, 2 molted to females; or the twenty-fourth, twenty-sixth, and twenty-ninth days after application. As no males were present the females were not fertilized and they only partially engorged. A second lot of larve was applied to the scrotum of a bull on April 18, 1908. They began to molt on the ninth day and molted as follows; April 27,3; April 28,6; Apri. 29, 2: April 30)01) sGim May 5, the seventeenth day after application, 1 nymph molted to a male, and molting continued as follows: May 6, 1 male, 1 female; May 7,1, and from May 9 to 11, 1 molted each day, and on May 138, 2 molted, the sex of the last mentioned not being recorded. The first engorged female dropped on May 17, or 29 days after attachment as a larva. Others dropped engorged on July 18, 19, and 20; 2 on July 22, and the last on July 26, or 38 days after having attached as a larva.
A third lot of larvee was applied to the ear of a host on July 1, 1908. They began to molt 8 days later (July 9), many having molted by the ninth day and all by the eleventh. Many nymphs were fully engorged on July 14, but did not molt until the seventeenth day (July 18), when 2 males and 2 females appeared; all had molted by the following day. Three females dropped engorged on July 27, the twenty-sixth day from attachment; a partially engorged female was crushed on July 29 and the last female was missing on August 11, after having remained mated with a male for 10 days.
THE TROPICAL HORSE TICK. 203
TasLeE XCVII.—Summury of parasitic periods of Dermacentor nitens on a bovine.
| Days following application of larve. Date larve applied. | Location. Larve molted. Nymphs molted. | Females dropped.
First. | Last. | First. | Last. | First. | Last.
1908. RM ANN tO ce Ochs Le | Scrotum 13 15 24 29 Not fertilized. pt Se See a gE Seer s eee ae Ue tap. 23253 9 16 17 26 29 38 Nr ce jo ee ee 8 11 17 18 26 41
LIFE CYCLE.
The larve are snort lived, living only 71 days in summer under the most favorable conditions; they engorge and molt on the host as soon as 8 days after attachment. Nymphs may molt as soon as the seventeenth day after attachment or 7 days after the larve molt. Adults may engorge and drop as soon as 9 days after the nymphal molt or 26 days after attachment as larve. In summer oviposition may commence on the fourth day following dropping and as many as 3,392 eggs may be deposited. Eggs may hatch in 24 days during the summer. An effective temperature of 930° I. appears to be required
for incubation. ECONOMIC IMPORTANCE.
In the United States this tick has been found to be of considerable economic importance in the vicinity of Brownsville, Tex. In Novem- ber, 1907, one of the authors (Hooker) accompanied by Mr. J. D. Mitchell visited the Carman Ranch, 7 or 8 miles north of Brownsville, where a dozen or more horses had been at pasture for a number of weeks. Several of these animals were lassoed and examined. Their ears were found to be literally filled with ticks of this species in all stages of development. The molted skins and excrement which had collected in the ears in large quantities were the source of a nau- seating stench. Bishopp observed similar conditions among horses, mules, and burros at Tampico and Victoria (Tamaulipas), Mexico, during December, 1909, all stages of the tick being present at that time. Hewasinformed that this is a troublesome pest in that region. Work animals become “‘touchy”’ about the head and sometimes refuse to be bridled. Several men stated that the ears of animals fre- quently suppurate extensively and that in some cases the distal half of the ear drops off.
Dr. N.S. Mayo, in the report of the Cuban Experiment Station for 1907, page 25, says: ‘‘ These ticks sometimes collect in horses’ ears in such numbers as to cause the ears to lop and the screw-flies attack the ear and permanently disfigure the animal.” The filth and decay-
204 LIFE HISTORY OF NORTH AMERICAN TICKS.
ing animal matter must frequently result in suppuration and exten- sive proliferation, as well as forming a suitable place for the breeding of screw-worms.
NATURAL CONTROL.
No natural enemies of this tick have been recorded in the United States. Cold appears to have a decided effect on both adults and larve. At Dallas, Tex., during the early winter of 1909, when a minimum temperature of 20° F. was reached, many engorged females were killed and the few eggs deposited by others failed to hatch.
ARTIFICIAL CONTROL.
This tick is undoubtedly the easiest species to deal with that occurs im the United States on account of the short life of the larve and the ease with which the ticks may be destroyed on the host. The frequent application of oil to the ears will assist in keeping horses free from them. One of the authors is informed by men at Tampico, Mexico, that kerosene and lard are frequently applied to the ears of horses and mules in that section in order to destroy the ticks. Reinfestation was said to take place again very soon, however, as no effort is made to prevent the dropping of the engorged females or to starve the larve. The keeping of stock from an infested pasture for four months in summer will probably be sufficient to insure the starvation of the seed ticks.
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1898. See Dalrymple, W. H. 1899. Ticks and Texas fever. (Louisiana Stas. Bul. 56, pp. 134, 135, pls. 9.) Moras, M. 1903. Sur le réle des tiques dans le développement de la piroplasmose ovine. (Compt. Rend. Soc. Biol. [Paris], vol. 55 [1903], No. 14, pp. 501-504.)
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NEUMANN, L. G. 1896-1901. Révision de la famille des Ixodidés, I-IV. (Mém. Soc. Zool. France, vol. 9 [1896], pp. 1-44, figs. 36; vol. 10 [1897], pp. 324-420, figs. 45; vol. 12 [1899], pp. 107-294, figs. 63; vol. 14 [1901], pp. 249-372, figs. 18.) 1902-1908. Notes sur les Ixodidés, I-VI. (Arch. Par., vol. 6 [1902], pp. 109-128, figs. 6; vol. 8 [1904], No. 3, pp. 444464, figs. 2; vol. 9 [1905], No. 2, pp. 225-241; vol. 10 [1906], No. 2, pp. 195-219, figs. 17; vol. 11 [1907], No. 2, pp. 215-232, figs. 14; vol. 12 [1908], No. 1, pp. 5-27, figs. 16.) 1911. Ixodide. (Das Tierreich, 26 Lieferung [1911], pp. xvi+169, figs. 76. NeEewELL, W., and Dovucuerrty, M. S. 1906. The cattle tick. Studies of the egg and seed-tick stages. A simple method of eradicating the tick. (Crop Pest Com. La., Circ. 10, pp. 32, figs. 8.) NewstTEaD, R. 1906. On the bionomics of Ornithodoros moubata, the intermediary host of human - tick fever. (Proc. Assn. Econ. Biol., vol. 1 [1906], pt. 2, pp. 74-77.) 1909. Ticks and other blood-sucking Arthropoda [in Jamaica]. (Ann. Trop. Med. and Par., vol. 3 [1909], No. 4, pp. 421-469, pls. 4, figs. 2.) Nis, E. P. 1898. A preliminary study of ticks. (Virginia Sta. Bul. 86, 1898, pp. 25-30, pls. 4.) Nog, G. 1908. Il ciclo evolutivo della Filaria grassii, mihi, 1907. (Atti R. Accad. Lin- cei, Rend. Cl. Sci. Fis., Mat. e Nat., 5. ser., vol. 17 [1908], I, No. 5, pp. 282-293, figs. 4. NorRDENSKIOLD, E. 1908. Zur Anatomie und Histologie von Ixodes reduvius. (Zool. Jahrb., Abt. Anat. u. Ontog. Tiere, vol. 25 [1908], No. 4, pp. 637-674, pls. 3, figs. 2.) 1909a. Zur Anatomie und Histologie von Ixodes reduvius II. (Zool. Jahrb., Abt. Anat. u. Ontog. Tiere, vol. 27 [1909], No. 3, pp. 449-464, pl. 1.) 1909b. Zur Ovogenese und Entwicklungsgeschichte von Ixodes reduvius. (Zool. Anz., vol. 35 [1909], Nos. 1-2, pp. 30-35, figs. 4.) 1909c. Zur Spermatogenese von Ixodes reduvius. (Zool. Anz., vol. 34 [1909], Nos. 16-17, pp. 511-516, figs. 10.) Nutra, G. H. F. . 1900. On the réle of insects, arachnids and myriapods, as carriers in the spread of bacterial and parasitic diseases of man and animals. A critical and his- torical study. (Johns Hopkins Hosp. Repts., 8 [1900], Nos. 1-2, pp. 1-154, pls. 3.) 191la. On the adaptation of ticks to the habits of their hosts. (Parasitology, vol. 4 [1911], No. 1, pp. 46-67, figs. 26.) 1911b. Noteson ticks, I. (Parasitology, vol. 4 [1911], No.3, pp. 175-182, figs. 2.) Nutrat., G. H. F., Cooper, W. F., and Rosrnson, L. E. 1908a. On the structure of ‘‘Haller’s organ’’ in the Ixodoidea. (Parasitology, vol. 1 [1908], No. 3, pp. 238-242, pl. 1, fig. 1.) 1908b. On the structure of the spiracles of a tick (Hemaphysalis punctata). (Parasitology, vol. 1 [1908], No. 4, pp. 347-351, pls. 3.) 1908c. The structure and biology of Hamaphysalis punctata, I. (Parasitology, vol. 1 [1908], No. 2, pp. 152-181, pls. 5, figs. 9.) Nurtratt, G. H. F., and Merriman, G. 1911. The process of copulation in Ornithodoros moubata. (Parasitology, vol. 4 [1911], No. 1, pp. 39-45, fig. 1.)
912 LIFE HISTORY OF NORTH AMERICAN TICKS.
Nurrau, G. H. F., and Srricxnanp, C. 1908. On the presence of an anficoagulin in the salivary glands and intestines of Argas persicus. (Parasitology, vol. 1 [1908], No. 4, pp. 302-310.) Nurrau, G. H. F., Warsurton, C., Cooper, W. F., and Rosrnson, L. E. 1908-11. Ticks. A monograph of the Ixodoidea. (Pt. I, Argasidze [1908], pp. x +104-+ 35; pls. 3, figs. 114. Pt. II, Ixodide [1911], pp. xix +243, pls. 4, figs. 192. Cambridge.) PacKArD, A. S., Jr. 1869. Appendix to the report on articulates. Arachnida. (Ann. Rept. Peabody Acad. Sci., vol. 1 [1869], pp. 65-69.) PAGENSTECHER, H. A. 1861. Beitrage zur Anatomie der Milben. II, Ivodes ricinus. (Leipsic, 1861, pp. 45, pls. 2.) Pierce, W. D. 1907. Notes on the economic importance of sowbugs. (U.S. Dept. Agr., Bur. Ent., Bul. 64, pt. 2, pp. 15-22, pl. 1.) Pounp, C. J. 1899. Notes on the cattle tick. Its development, life history, habits, and geographical distribution. (Proc. Roy. Soc. Queensland, vol. 14 [1899], pp. 28-38.) Pycrart, W. P. 1910. <A history of birds. (London, 1910, pp. xxx+458, pls. 34, figs. 50.) Ransom, B. H. 1906. Some unusual host relations of the Texas fever tick. (U.S. Dept. Agr., Bur. Animal Ind., Circ. 98, pp. 8.) 1910. Eradication of the southern cattle tick. (Advance print from Proc. 7. Internat. Zool. Cong. 1907, pp. 8.) Ricketts, H. T. 1907. The role of the wood tick in Rocky Mountain spotted fever and the sus- ceptibility of local animals to this disease. (Journ. Amer. Med. Assn., vol. 49 [1907], No. 1, pp. 24-27.) 1909a. Investigation of the cause and means of prevention of Rocky Mountain spotted fever carried on during 1907-8. (Bien. Rept. Bd. Health Mont., 4 [1907-8], pp. 77-191.) 1909b. Some aspects of Rocky Mountain spotted fever as shown by recent inves- tigations. (Med. Rec. [N. Y.], vol. 76 [1909], No. 21, pp. 843-855.) RoBertTson, F. H. 1905. Fowl tick experiments. (Journ. Dept. Agr. West. Aust., vol. 12 [1905], No. 6, pp. 561-563.) Rosinson, L. E. 1908-11. See Nuttall, G. H. F. Rone, C. J. 1909. Estudios sobre Ixddidas do Brasil. (Rio de Janeiro, 1909, pp. 220, pls. 6, figs. 30.) SABBATINI. 1898. Fermento anticoagulanti dell’ Ixodes ricinus. (Gior. R. Accad. Med. Torino, 4. ser., vol. 61 [1898], No. 9-11, pp. 380-395.) Satmon, D: E. 1884. Geographical distribution of southern cattle fever. (Rept. U.S. Comm. Agr. [1884], pp. 252-258, pls. 3.) Satmon, D. E., and Stizzs, C. W. 1901. The cattle ticks (Ixodoidea) of the United States. (U.S. Dept. Agr., Bur. Animal Ind. Rept. 1900 [pub. 1901], pp. 380-491, pls. 25, figs. 192.)
BIBLIOGRAPHY. 213
SAMSON, KATHARINA. 1908. Die Eiablage und die Larve der Zecke Rhipicephalus sanguineus Latr. (Sitzber. Gesell. Naturf. Freunde Berlin [1908], No. 2, pp. 46-50, figs. 3.) 1909a. Zur Anatomie und Biologie von Ixodes ricinus L. (Zeitschr. Wiss. Zool., vol. 93 [1909], No. 2, pp. 185-236, figs. 18, tables 4.) 1909b. Zur Spermiohistiogenese der Zecken. (Sitzber. Gesell. Naturf. Freunde Berlin [1909], No. 8, pp. 486-499, pl. 1, figs. 7.) Say, THOMAS. 1821. Genus Ixodes (pp. 75-79): In An Account of the Arachnides of the United States. (Journ. Acad. Nat. Sci. Phila., vol. 2 [1821], pt. 1, pp. 59-83; Le Conte ed., vol. 2, pp. 9-24.) ScHROEDER, E. C. 1907. Notes on the cattle tick and Texas fever. (U.S. Dept. Agr., Bur. Animal Ind. Rept. 1905 [pub. 1907], pp. 49-70.) Smuveson, J. C. 1901. Case of a parasite—‘‘Argas (or Ornithodoros) megnini” (Dugés)—in each ear (Lancet [London, 1901], I, No. 4052, pp. 1197, 1198, figs. 3.) Suira, A. J. 1910. A new filarial species (Filaria mitchelli n. sp.) found in Heloderma suspectum and its larve in a tick’ parasitic upon the Gila monster. (Univ. Penn. Med. Bul., vol. 23 [1910], No. 9, pp. 487-497, figs. 9.) SmitH, T., and Kirpornge, F. L. 1893. Texas fever. (U.S. Dept. Agr., Bur. Animal Ind., Bul. 1, pp. 301, pls. 10, figs. 7.) SPREULL, J. 1898. See Dixon, R. W. Stites, C. W. 1901. See Salmon, D. E. 1910. The taxonomic value of the microscopic structure of the stigmal plates in the tick genus Dermacentor. (Pub. Health and Mar. Hosp. Serv., U. §. Pub. Health Bul. 62, pp. 72, pls. 438.) StTocKMAN, S. 1908. Redwater in England and itscarriers. (Journ. Comp. Path. and Ther., vol. 21 [1908], No. 3, pp. 225-232; Vet. Journ., vol. 64 [1908], No. 401, pp. 538-548, charts 4; Vet. Rec., vol. 21 [1908], No. 1067, pp. 391-401, charts 4.) Stott, Orro. 1890. Arachnida Acaridea. Family Ixodidez (Biologia Centrali-Americana, Zool. London [1890], pt. 84, pp. 18-24, pls. 3.) STRICKLAND, C. 1908. See Nuttall, G. H. F. TAYLOR. | 1892. [Crotophaga ani.] Auk, vol. 9 [1892], No. 4, pp. 369-371.) THEILER, A. 1905. The transmission of East Coast fever by ticks. (Transvaal Dept. Agr., Ann. Rept. [1904], pp. 135-158.) 1908. The influence of cold on ticks and Piroplasma parvum. (Bul. Soc. Path. Exot., vol. 1 [1908], No. 8, pp. 451-454; abs. in Journ. Trop. Vet. Sci., vol. 4 [1909], No. 2, pp. 223-225.) 1909a. Diseases, ticks, and their eradication. (Transvaal Agr. Journ., vol. 7 [1909], No. 28, pp. 685-699; Transvaal Dept. Agr. Farmers’ Bul. 63, 1909, pp. 15.) 1909b. Report of the government veterinary bacteriologist. (Transvaal Dept. Agr., Ann. Rept. [1908], pp. 55-97.) 1911. First report of the director of veterinary research. (Union of S. Africa, Dept. of Agr. [1911], pp. 275, pls. 19, charts 2.)
214 LIFE HISTORY OF NORTH AMERICAN TICKS.
THomeson, W. 1911. See Mohler, J. R. Topp, J. Ts 1905. See Dutton, J. E. TOWNSEND, C. H. T. 1893. Ticks in the ears of horses. (Journ. N. Y. Ent. Soc., vol. 1 [1893], No. 2, pp. 49-62.) VERNEY, F. A. 1907. The influence of frost on tick life. (Natal Agr. Journ. and Min. Rec., vol. 10 [1907], No. 12, pp. 1550-1552.) VoorHEES, J. F. 1911. See Cotton, E. C. Vorontzov, V. E. 1907. Anatomy, biology, and pathogenicity of Irodes reduvius. (Anatomiya, Biologiya, i Patogennost Kleshtshei vida Ivodes reduvius. St. Petersburg: Govt. [1907], pp. 41, pls. 3.) WARBURTON, C. 1908-1911. See Nuttall, G. H. F. WEBER, A. 1903. See Kossel, H. WELLMAN, F. C. 1906a. A note on the habits of Ornithodoros moubata. (Journ. Trop. Med. and Hyg. [London], vol. 9 [1906], No. 14, p. 215.) } 1906b. On a hemipterous insect which preys upon blood-sucking arthropods and which occasionally attacks mammals(man). (Journ. Trop. Med. [London], vol. 9 [1906], No. 6, pp. 97, 98, figs. 3.) 1909. See Wherry, W. B. WHELER, E. G. 1899. Louping ill and the grass tick. (Journ. Roy. Agr. Soc. England, 3 ser., vol. 10 [1899], pt. 4, pp. 626-644.) 1906. British ticks. (Journ. Agr. Sci., vol. 1 [1906], No. 4, pp. 400-429, pls. 6.) WaHerry, W. B., and WEtiMay, F. C. 1909. ‘Ticks on the California ground squirrel. (Ent. News, vol. 20 [1909], No. 9, Di 3/62) WruiaMs, S. R. 1905. Anatomy of Boophilus annulatus Say. (Proc. Boston Soc. Nat. Hist., vol. 32, No. 8, pp. 313-334, pls. 5, figs. 3.) Woon, H. P. 1911. Notes on the life history of the tick parasite Hunterellus hookert Howard. Journ. Econ. Ent., vol. 4 [1911], No. 5, pp. 425-431, pl 1.)
IN Dix,
Page
BEeLrT (ulote I Derinacentor UCHURIUS s,s ss 252 Se Se oe eee eee ee eee 35 Agelaius pheniceus. (See Blackbird, red-winged. )
Amblyomma americanum, adult, deseriptive...........-.----.------+-------- 142 BERD ONY teres ok sees See os wk eee 3 148-150 GOL IGl AtMOAt eee ae re ese bole e ede cok nee 151 if A ag OE oes ee oe ee 151 REDD Vee eens hore ee elses clos ok oho soem at 142 @istribithion ceasruphted lS 2222s Loos eae ee 143-144 Zonal, 1m North Ameri¢a..-..2.22...+5% 22 CCOMOMIME TA pUETNCe- 92325. 6 oe esa oo 2 he ttle 150 COP CRC TAN Ee es ee Se ie ad oe eee ees 142 hile Weer ees as beeE eee os oo ke es ®.. 144-145 egos deposited “mumber. . 522/20 ce cos se eee et ee 33 host welatigmaay oe Fo oie te eke et pease 142-143 Lepbyae Geach PL ayin ee See ee ei eee sec esas eee 142 Vine AGO oe dae abe ss 2 wie Cae Caine 146 Die ye lee aes ay py ee = aig Wace Suds Che 150 islony mons ss are mec ee. Feces os ..-- 144-150 IOHSeVvILy OF slages,.maxamigm 22. ool... 2 eta snk 71 PsA pimersnen Ne ees oes Se oe te he aes <b saat eae 29 with female of Dermacentor nitens............- 201 females of other species of ticks......... 149 not an agent in the transmission of splenetic fever. 123, 150 Vib Lie at |) 2 ede a 142 eet ane te Sete ue os SRL be 146-148 periods in life history, maximum and minimum..... 70 Workson brolosy apt BOs Se ISS cee wee ee se ewe 20 GUENNPNSE, AUGIT, CESOTIPIIVG een. oe c08 5 oe See ee ee eee se eens 151 bike Weare ROW 156-157 COUUGHOL PiU e Ee Oe SPSS cic a clase wh wk vee ues cms 158 egg NEES oe re eee 158 ea (a a SRR | lee ie is ce ee 151-152 distribution, geographically 20220202... 2. 0a icc cens 152 zonal, in North America. ................ 21, 22 SUOMOMIIG IMiNOrANCEts 68 Jes ss SSUES 0 ee eee 157-158 Bee GGRERIN i yONa eGo eek tS ete ae tees k san ch eWie wee 152 Uhre NG Oe Sets Pe Oe ee Oo ee Scns cnt Ss ace 153-154 eggs deposited, number. ..-.. eS ee 33 TORU PEMTERIBEIE E oF R TAS hacen osha eran geek 152 Cs a. are 151 jog Cee Re a ee 155 hg gel Ns ee ee a, ae 157 Die oy SONG Re) oe ee 153-157
longevity of stages, maximum. ...................... 7
216 LIFE HISTORY OF NORTH AMERICAN TICKS.
Ambliomma, cajennense, nymph, descriptives 2%) ue: ace ee ee Life: haistoby. ey tote semen wee Ce eee Es Me periods in life history, maximum and minimum pest to man im Jamoatea.sasose eee eee ee ae ee coronatum, oviposition, first description of process.............--- dissumile, adult, descriptiver. = sc ste s2 a5 ese eee ee eee 130 Nite HaSbOr yee ose se ae fe ee ea eee re a 134-135 Control, wari al 2 eee Ga lees oe ea eee 135 Gescnipuive?co 05. oo . ee. See eae ee eres 130-131 dissentingtien soe. so ae he Lak gob Gates 34 distribution, georrapliicalw ays etal 4) aes ae eee 131 zonal,-in. NorthiAmeriea. 22.2 25..0225.58 21,22 economic importance. 4-525. -- 2 4sa25- Niches ee ae See 135 ese, (Gescriptivel jc. \aseiser ae snc Le Nee eee [Si Lite hispory, ca Pw ete oc ec 131-132 eves deposited: number. teae eee os os ks eee 33 host rela trons caseyae saa eet ee 123, Toit larva, Ceseriptivempitecead’ yacde Mie fae ey ae 130-131 lie History: us Maes aaeoe st See eet eee 132-133 . lite cycles eo. 228. eee ee Oe ee eee 135 HISCOLY 3. oc od ee ae Gee eid a oe ee eee 131-135 longevity of stages, maximum. b.02.2.0- 2.) 30522 yee i nymph; descriptlve se-ccetenh: ass Soe eee 130 Late: HAStOry steer Aiko ste ee aoe 133-134 periods of life history, maximum and minimum.....--- 70 general MeCCOUNb sso ee ea a Pe eae 123 “Goldin, Wost rela tomptiyy s-e see eee Oe ee Is studies 1m 1900. 0 5 Su eee et tae eee Eis) ene 123 hebreum, agent in dissemination of heartwater of sheep, goats, and Cathe sect axe: ceiryeae Se eke Se 2 are a ee es 123 biblioeta phic referemecers 0.520! oo se oe 209 detachment afterideath atdtosts:-2222 2223-5043 5)2 ao see 72 epps deposited, manamumies) 2506. 22 cse 5 sce ee 75 TUNDEH ene atieye ak See Sens 32 mating halbitse ced 450 \uaiik Uganda 30, 31 studies 1m 1899... et Bee oe FA Se cee er tei Pena 123 maculatium, adult; deseriptive-ya-seee seen ose et = a eee 135 Tide, agtOiy 25 seat pave 2 Ee ea ene ae 139-141 control, artificial). teeeens ewer aoe eee eres 142 ACU ee alked sete en en ee ea 141 descriptive: .caijaeede ee eee ee 135-136 distvibuiion speortaphical yess c8t) oe eee eee 136 zonal, in North America... 2.252.) 22932 2122 economic importance nays: nee eee ee a eee 141 eon. Ceseriptivies.: 3. sede Wee os oe ee eee nee - 136 life history ieee 1 se a8ee Ube BA aca SEC Ae a mike 137-138 evos deposited, maximatmmd 295 2482s oe oo bees 75 NUMIBCE ee aS: ee sO SO ae 32, 33 female mating with male Amblyomma americanum... 149 host relationships). 2: os aban ee oe enor 136 larva, descriptively <5. fae gee ee ees ee 135-136
life Ahistory fqsu4 see ee ae ie nee life cyeley wi. c8t co ee eae eis ao ee nee eee 141
INDEX. 917
Page.
Amblyomma maculatum, Vile history. 222-266 secccecssteccee sects esas ede 137-141 longevity of stages, maximum.......-.. rates 71
males more commonly collected than fe siviles’ ate 76
YUE) COREG 2232 Seto 2) oe 0) esos 135
ine history 2155220222222. - SED ee
periods i in life history, maximum Vand minimum... . 70
pee bes eter ee ee ee ak et nie te 123
marmorcim, host relationship. 2.2222..2 2529252. 22.2 ecl ls 6 IB ce OS OME A pn) ey 123 Be ming pda teg ge Et a el ee aed 31 tubereulatum, adaptations of habit- =. 2222 -.2.52-------.-------- 28-29 enn, SCENE AWED Pee ec ole eM Wo oe 123-124
Penney et eer ee eee) oo 2 toca oe 129
attachment to carapace of turtle.-................- 72
ne ag | an tee ae a a 130
Cesciiphiyetess eee se ee ee es 2s 123-124
distsipuntel, penrrapliseal. 2.2 2.2-.2.:22-..--2-..-- 124
zonal, in North America............. yA Way
CoOmannnie StIeEMAMO 7 > oe oe ee 130
poy reap me ee et ee 2s 2a tS SO 124
A lee ie i od Se ee 125-126
ele depamued, nemiber! £32 22.5224 22-5223 33
pe Pea A Py Re ee ee Se ca 124
Tighe Geen FA kN kn 25
ear eae ee ne cock sl
bits a os cee tie Ot SMS nh nk 126-127
Ma eK go Ee Ae eet es ie 129-130
Riding G8! = 2. OTS EON 125-129 longevity of stages, maximum.................--.- 71
males more commonly collected than eralen arenes 76
epee, ewrtapmiavGs: oo ete s he cee 124
Eeereienty aes Sean os 127-128
periods in life history, maximum and minimum... 70
° vesica biloba and its use in oviposition. .......... 73 tr ee LL ee ee or oe ee ee 32 et al ere ie i ed eg cine 34
cers deponies “marmite... SESS he 3 2) 75
NRE semene. Mera oe a 32
Bien ae) Eee wna ee es cle a ees 2 Se 20, 123
ca ia Eni Re Rg gs ae ig ear” SOE I be 123
nme Lace Tick Om retin s+ SETS Ok eds a se 129 studies in 1908 222..<5 5225.5 ah fa Nt pa Anaplasma causing fever in bovines, traneiniation by Maryaropus soe toe eS 111 Meenas CONE 2s oe Po Aer Ate as ee, OS SAA ee 44
Ani. (See Crotophaga ani and Blackbird, parrot-billed.) groove-billed (see also Crotophaga sulcirostris). host of Hemaphysalis leporis-palustris. ...........--.--+-+-- 90 Anteater, host of Amblyomma cajennense...........----------------- eee e eee 152 Anticoagulin in salivary glands and intestines of Argas miniatus.........-.-..-.- 60
Ant, little black.
(See Monomorium minimum.)
Ants, enemies of Margaropus annulatus australis..............--------------+-- 122
Aponomma tnornata, distribution, zonal, in North America
Apophyses of mandibles of ticks, definition...................-.-.--....-.---- 16
218 LIFE HISTORY OF NORTH AMERICAN TICKS.
Page Arpas adaptations of habit s)s. 25 28526 eg See a 28 americanus, bibliographic rererencesas ten ce sea) eee 206, 207 brevipes, distribution, zonal, im NorthaAmencacssss)sue- 2) lenge fe 22 in United Statesoiss. 6 2 eet ie aie alga aap are 45 general “aecoumi. 2000 ee eee oa maa deca ee yl cece 45-46 Minidtus, aga ptations OfMap it le.1g6 haat eee eatin Ue eh Ok ee eae 27 SIP IO UCIE OU He eam eaUeeOtes st enn Castm Sera sty iat oryl Ale ee AN. 26 adult, icdeseripbine 220 |. eke os ae eee ee i eg 46 life history 212\2iy5.- 1 MU Oe aaa Cahn ie eee 58-59
agent in transmission of Spirocheta gallinarum and S. anseri-
TUNING at LOW IS eis es NAR OO ON Sal ae pe ee ea nae 46 bibliographic references: 2.54. 4k Ae Gee Uh fa ee ee 208 control, amtahi eral ci. 43 eee awe ae ata el ey Sleep A ae / 6h
WUT is lane ec ea pala A silt heey faye carlo elles Oana 60
eSCrupUIVi. sere Wier wk eG SrA talh Bi) Ad Rite Ls Dyn etee rece a 46-47
distribution, @eographiea li 2 cee eek ie ae ek el ah oe 47
zonalim. North Amenie¢as i.e) 52.) 8 Ase oe eee 21.22
CCONOMUC Importance... Cee ae ues see a 60
ego, GeSscriptiversi. cuore ute Ml hee LA) ellie 1192 ome gees 47
Wife InastOry eo) cic Soe eee kien la a oe cs 47-53
egos deposited, anumiber-: 5 ale et hue te ee eee 33 | OF) 6h: Meme Re RUN Ae TON SONGS UIP Meera ie cr AE) 46
host relationship... 5 Pace ues eu a ah 0 eee 47
larva, deseriptive Ge is seh ae ke Re alec ee ee ee ee 46—47
Like. Tnistor ys. 308 hcd ioe Rar nce cs pag ha eal er es Ee ae 53-55
Vide @yGle socia.s ois 2 gate eee ei Fee a cate a a a ea 59-60
Iniotory. Jrat ahd he eS oi a cep ee 48-59
Nos cVegon Gah gime tt: 9-071 05 cs Ree eet ere MM Sauer Mepis aici fA 45
innate Tal baie ig deed ag a Gert eS He eee 29-30
nyMp hs dieserip tly eaa% 4.4.4 sceu a berg ok Oe a See oa ee 46
| Te) 00 F:) 01 9, meer Cam AME wader ONE Ua Meee DP] fara e Me I 55-58
rearing Methods. 5274. po keels Lee a tie ell A ee ees 39
BECTELIONS co: fosue 8 Seg ye i a We aN ee 31
persicus; bibliegrap mic relerences. wae oe. eee ee hep) wa 207, 208, 212
1(6 (25 01 6, Seen gel OR Pye OLE ea Ss) VT EANMp i ucla Lak Tots Spheres = 45, 46
Tati Waite oon «ae lo wa a nae iN aL hile. 2a ey ae 30
reflexus, \ECONOMMIC IMpPOTtANCe..05. 2, W412 - Ae Ne eee ea a eae 45-46 erroneously reported from United ‘States... .- 2.22 422242246 45
parasite. of fowls. 21.00 cil eae cect ee) fut) sl a anor 45-46
Sp:, bibliographic referemees ya /h) el epee os oe olde = see 207 talaje, bibliographic reierence 220.2 J 95 ui, eae ele le ee ee 208 Arvastdes, developrment - oie. .5 acto 2:-sSisce sh ee RN Be aye es eee 45
Ass (see also Burro and Donkey).
host. of Dermacentor nitens <0 200.) eet a sy eee 198 OCCT C NON Neco i Bet Seine labs Aker ae aes ie atin!
POTTED TAS 5 oe he Pi a BR ss yell espa oe, ola 191
VOTUSEUS Soi se I dh ay Se Spay esl cl aii a le RI aearas Se Re 166
Ornithodoros, Meqnimt 06292 ees ee a er le ae aie 62 Badger, host of Amblyomma american win. 4) Se ae ee ia 143 Dermacentor: varrabilass sc. 3 08 sepa eile esc ae ee ie “191
MON IUSTUS Je coho eS A ae pal ag oe aie ad ea 166
TcOes Vetiver sos Bias So cane tl al eto me eee 82, 83
INDEX. 219 Page areranid lOngicouda, CNCINY Of TICKS. 20.00 2< ecw noe awe wads wecscsapersue 43 Batrachians, probable enemies of Hamaphysalis leporis-palustris........-..---- 96 Peat, prown, host.or Dermaccnvor VENusis ccs ke cst ewencececceccteceesercce 100 ectie; im Of AMDIVOMIMG VIDETOULAIUAN, 66.2 nc cd one cc oe ee ee ales vee nn eee 13 Pram, Ciemies ot Demmnaceniior vartabilis. _. 0... c- e e e e ee e a 197 el OMB CR ONOCNIM = 25632210502. Meee teeta yawese ts, - ee eens eee eer ee ee 2 ees een eeees 42-43 OI os EEE eS Re Ls ee eS At a en 46 MMOL LEB Rene Neh Ok a ere og 2 ak ns a ge 77 it PUP a SORGUINGUR 08. Pe. Pe 8 ee ee ee 103 Blackbird, Brewer’s (see also Huphagus cyanocephalus). host of Hemaphysalis leporis-palustris.............------- 90 CNGGRY: GLE CERIACATIION VENUSTUR. . oc sone) Baines eee we bates te ee een 180 parrot-billed (see also Crotophaga ani). enemy of Amblyomma cajennense........-.-..----+-- 158 fea-waneed enemy of cattle tick 221.304. 02- 2220-22 lle eee 42 host of Amblyomma tuberculatum.....-----.-.:2-......-- 136 Fipaia pnyselis CHOTAQING LS. Seo 2 se 97 savannah. (See Quiscalus cragsirostris. ) :
Species Wiktiowl, Guemiy OL fiCKS.. 220-2 2bbee eel be wesc eae cd et 42 Blackbirds, enemies of Margaropus annulatus australis...........------------ 122 Blastocerus dichotomus, host of Margaropus annulatus australis. ...........---- 117
panidesng——B lastocerus Ciechotonis . als. ss oe ee oe eee 117 Pine bug, colloquial name for Argus mitiatus. .. v.22... - 22022-2222 ee eee 60
jay, nos of Axemaphysals leporis-palusiris. ... 0.02 0.-.2-2 2222.2 ee <% 90 PEGE GCE I ia Ree AN ae of RE Gragg N oe Se ee, eer 77 Boophilus annulatus (see also Margaropus annulatus and Tick, cattle). bibliogtapime teterenee oso) eos doe es dee cc eeec. 214 australis (see also Margaropus annulatus australis). iiblionmaplumteterence: 0.225202 292.202 22s es. aces 205 Bovine (see also Bull, Cattle, and Ox). Hosier Ambion amencomum. =. OSA 2k 146, 148, 149, 150 Re ete ees a oS SECA SSE ER a 155, 156, 157 WIRD eS See Ae ee tid ee nce eae Se 132, 133, 134 Viger ete poche aco act oor ul bce es calee 139, 140 LUDO AMATI ete oer see oe ees ee Lk 127, 128 Dermacentor nitens.......---- el eee ete hte Bate ASE) eae cee 199 moebntaha fe Sy Ne! 181, 185, 186, 188 parumapertus marginatus. ......--- 159, 161, 162, 163, 164 NANADWIS is so bet ae ceases laa lx 194, 195, 196 VENUSNUS s 25 isk525 » rawce LOTS EVO; U7), 1738, 175, 176, 178, 179 DIS AR ERR 252 oS OILS VOILA 100 eporis-rsatuairig. soo PSEA TI HSE Se nisiwien 93, 94 PLOMGS TANG Soe seok Passos Poe sl Oe ee ee Peer reer 86, 87 POR PC Siae ee See a eS OLIN LUGE AR 79, 80 MR ORGERR DUR GRAINS ood, os Sd ESE OOS SBR AS 112 CIPRUINGEOT0S WAGAM sn C2c5osoon. ce oe aeka ye Me SSCA 67 Ihe mmcepndiis sungutneds <5. Se PUR oie snes 107, 108, 109 PERE Ut COU TAL HOC EB saa, Sees dees w lt. Soke eee wets Soe ete’ 44 Bufo marinus, host:of Amblyomma dissimile.. 5 Soe le 131 Bull (see also Bovine, Cattle, and Ox). ELT LerniiCeniOr RUOMDic. sess. es ok PUL Ne eh 2 aA 202
220 LIFE HISTORY OF NORTH AMERICAN TICKS.
Bullfrog, colloquial name for Bufo marinusin Jamaica..................------ 131 Buphaga africanus, damage inflicted on imported domesticated animals in PEP CB oo ee eye a eS ee ee eee ie 43 enemy ol ticks in South Attica... 4 0.002 c see eee 43 Burro (see also Ass and Donkey). host. of Dermacentor nilenga. 5.05 <2 esse ee ee ee eee 203 Callospermophilus lateralis cinerascens, host of Dermacentor venustus..........--- 166 Galomel against spinose-ear tick 52 oss oo fo ce ee eee ee ee a a 69 Camel, host of Khipicephalus sanquineussc a2... Sp- gees ohio a ee ee 103 Canary, ost OF ATQGs MiVIUUS cine esc aaron Soe See ae oe eee 47 Capitulum of tacks, desertpion.. 3... esc soe hee ec a ee ee 16 Capybara, host of Amblyomma cajennense..- 0.22 = soar eae ae ee 152 Carbolic acid and sweet oil against spinose ear tick....-.....................- 69 Cat, host. of Amblyomma americanum a. .<cwcwesanis 52 no ese we oo oe eee Deriegcentor VONUSTUS oo. ae Scion oe eek a a ee ee 166 Hemaplusalss leports-paliistrs sein ce Sie A ee 90 Oriithodoros MeQaitt = des 0 oe ee See 5b 4c eee 62 ihipicephalrs SOnguinews.. «2 ceo. 2 i ol 103 wild; host'of Dermacentor pariabilts 3 Ls 8 a oe aA ae eae 191 VOT USCIS ar a era oh Na eg Sea ee 166 Cattle (see also Bull, Bovine, and Ox). Brahman, larsely resistant, to ticks. 920 so 598) ee ee 44 hosts of Amblyomma amertcantwm <<. 2 ve ees ee 143 COERTLCTUSE Ra te eh os ca eg a 157 Liber eUlALUNR 05 Seo aes eid Mee 124, 130, 136, 141 (Den GCENIOT OCCUR ENNIS se ns Re ee hae ee 182 DOTUU SOUS sinh aR a ce he a ee 166 Tiga hes SOO PUI a ai a a al) ets oy ee ee 77, 81 Margoropus annulatius australis jn... 2 els 222k eo eee 117; 488 OTrntthodGros Meg WIN a 56 een ad ee 62 Ceratixodes putus, distribution, zonal, in North America......................- 2122 1105 11: a he nee REP n ee Fe aunyene ae a CMP 30 maenatus, distribution, Zonal, im, American. te). 2.02 eee 21, 22 Crrvms ving ininnus—Odoniperlus OMETICOTUS. «oe 8 oe A ae os ee We Chicken, prairie, host of Hemaphysalis chordeilis............--.-------------- 97 Chickens (see also Fowls and Poultry). enemies of Dermacentor venustites: 1) a ee 180 hosts of Amblyomma amerteanwi. 0 356k) eee eh Soe oe oe ee 150 AT SAB wns) ainjeaiets 2 Se iors Sane See rain Ee ee 46 Spirocheta gallinarum.......------- 46 Chipmunk (see also Eutamias lutewentris and pee Bol eran: vena host.of Dermacentor Venustuse op tec = eee ee eee 17 Bipods RANG sa 8 vic oho gs) tela BGS Bae a te Pe Rn ere 82 Chloroform and sweet oil against spinose ear tick.....-..........--..-..------ 69 Chloronaphtholeum against spimose ear tick = 5. 34603 e oe poe gee eae 69
Chrysomyia macellaria (see also Screw-worm fly). eges deposited in woundsmade by Amblyomma maculatum 141
Citellus columbianus, host of Dermacentor venusius..<.-.<-2-20+-+--i----------. 166 Ir0des Wing oc wench ee ies ns ae ee 82
Cock, chaparral, host of Amblyomma americanum... 25 epee ea eee 143 Hemapliysals\lepons-polusirissc. i282 75) see eee 90, 94
INDEX. S21
Page, ac Se conttov ol Damacentor Wiens... Joists sel het iin win oho wee den tenis 204 errs baa nk fee ae eat gat Sor eee ISP nt wate 41-42 innsts osmpragiaenemwvek tipkas< > Sa3. i atesi ce - wi. eet thas). ---- enone 42 oueeed, 01. araimst epmmose ear tick....-.-..-525 220 2\0t5s 22 2d----- 2 eee ee 69 Cowbird, eastern. (See Molothrus ater.) red-eyed. (See Tangavius xneus involucratus.) Geaoic. Dost we Ambivonme cajennense... 042-2 2s SE ed eae oe ee wee 152 Dn MAP OUIS.. 2 S25: eds psecte SE views i was nd 191 GG are eens negate: seg ee. 232s Ze 166 EE OS) 2 Oe oe a te 61 Crotophaga ani (see also Blackbird, parrot-billed). Sueepenite setenemCe= oo. 00 oe Seek Bab ey. eo es nn os 213 enemy of Margaropus annulatus australis..............-------- 122 eR a Ce. ee Me SoS ae ee caee 42 sulcirostris (see also Ani, groove-billed). PMG ORCRINO AMO: cress. eS ee se6. 22k. a. se 42 3 Margaropus annulatus australis.....-..-..-..--- 42 Crow, fish. (See Corvus ossifragus.) Pumice Pudue, bibliopraphic reference... 202.522. 222s... 2... 2 etn a 208 Deer (see also Odocoileus toltecus). black-tailed, host of Ornithodoros megnini ......-.--.-------- fel ined he ae 62 Ramer -cmpiOMnG amecinim ct eo Soe ere. 2 ee 143 CUCM CRC Ci. oe et oe eee 152 Prone mee ent ee, oe a oe fee 136 Po prene nid Ales eee es ccs: SIR Pe aE wk ook ee oe ge og 198 Mipseenniaa a Et tO. or aay Se ee) AES eae bes Ree A SR Ok hy 191 i ee ae AIL SP of 5 Sac nsec 77 Morjgarapusmnnibiiis australis. 222.0252. sic. 2-2. <.-+--2e- 118 marsh. (See Blastocerus dichotomus.) Virginia white-tailed. (See Odontocelus americanus. ) Dermacentor Gibipiwctus, activity during winter. ....2202.2....-.-..--.----.-.<.6.: 35 PRU DEG ts 0 gS | ae aoe ea a 26, 29 distribution, zonal, in North America...............-... 22 Rongertiniohiarwase Se Coes 2a. so ee 71 SNORT MMNNS Sere pee os sae yom ~ ww v's 5 Oily Oy UE gy Laas a ee ae ee ee 213 peecime—llermacenior varsabilia 2226 ohcee a Sk os eS ek ee 20 emseb tiie UES Dena tee wat tau sere os Dork OL es news 158-159 eemsnas amend uae etal wee Je) Bote ss a ees ee 158-159 nigrolineatus, distribution, zonal, in North America. ........-..-.-- 22 puens moapiaLIOne Of DAbibet oo... SG - 2. 2. SS. es. cs DOD Se ey ee ee a 197 Pune ts Meteo 2 OSs 201-202 pomivel: amtiiames scot ebaech sie eee acess ei sae suki ed Pa es Se iis Fe bat sew Swede 204 PIII gt Cotes no fre Ney eh Shen cae ws kde 197-198 distribution, geographical. ................-. Cy ae 198 ponal, in North America. ................... 21, 22 ce i 203-204 Gy MOGNIN ace PaO re). irs Ss eS i wes ewe eed 198
Oe ov-ve 100
992 LIFE HISTORY OF NORTH AMERICAN TICKS.
Page
Dermacentor nitens, eggs deposited, number!.... 2 9U eae ee 33 GREE LOM Basen a yey one ceo eet cne ne ea ail female mating with male Amblyomma americanum........- 149 host relationship? 2352/5 cu ee Seg 198 larva, deseriptiveus.<.: 4 ee ee ee ee 198 Tiiehistory< tess Mien ee res 8 nent es eee 200-201 nde yl sess 00 ae yes Se EES ee ee 203 BIstOryiice cle eats So Ae 5 BE Se ee 199-202 longevity of stages, maximum..... ESR e) ose NE er ee 71 mating jaa bitisies = asks ig eee eee on with other speciesiof tieksis4 4.42 fe Ae keee Hoe eee 201 moltime tbabwige:) i. ose 5 Bee ee ae ee 25, 70, 158 nymph, descriptive: (Less Sn Se. i ee 197-198 life Insbony Aa se ee SRO eee ce ee 201 parasitic periods divs see eR Re eee aie 202-203 periods in life history, maximum and minimum.......... 70 occidentalis; adult, descriptive see Saga ee 4.2 5. 2 hoo Poser Ses er P 181 fife history... 22 are RA neces aes 187-189 control, artificial. sue ee eee 190 : Hatiral. 2. 22/20.) Se ~ 190 deseriptive..iasasensce ete yao Bee ee 181 distribution; géozraphicalecs..) -xiuee css see ae 182 zonal in) North ‘Amenica. 2. 2.225.225 522 22 eConomic InIperiance. sees aaa is eee 189-190 eps, descripiive! 2.2.0 3 5 eae eae 181 life histotys2.12: 6. see gee eee 182-184 eggs deposited, numbers). ea ena Pe es ee ee 33 host relationship. .°22>-4e2- a eee ee 181-182 larva, deseriptlve..ss wary as ely ny BY. eee eee 181 lite history =) Se eseeeisa sae ee ee 184-185 life cyclert2 soos). See ae. ee eee 189 history i225. 2:2hel.42 Pear ep eet ot Oi ae eae 182-189 longevity of stages, maximums le 2222S ee 71 mirolimye halts: so...bows aac) Se eee 158 name wrongly used for Dermacentor venustus.....-.- 182, 189
Virginia record of Amblyomma
macniotmis. Jn 2 SUE et Ie 136 nymph; deseriptryersistas se sas eles eae 181 hifev history: we. se RD OE Rees ie 186-187 periods in life history, maximum and minimum.....- 70 parumapertus, distribution, zonal, in North America.........---- 22 marginatus, adaptations of habitulis: 22 2se8es 2622 - 2 adult, deseriptives: . 22542: - Borat an 159 control, naturales me. cas eo ee 165
descriptiverest) 2h tensescati 2 Steeles 159
distribution, geographical........... 160-161
zonal, in North America. - 22 economic iimporiameet ss. -... 20.25.2522 165
ery, desenpiive eis ko: tee eee 159
life daishoryg eS 2oe ek et aie ee 161
eggs deposited, number........-...--- 33
host of Hunterellus hookeri.....------- 165
relationship eM Ly Roe 25, 159-160
INDEX. 923
Page Dermacentor parumapertus marginatus, larva, descriptive........-....-------- . * 159 Mog 3 My og ne 161-162 ECV CMe eae Oe 2 eS 164-165 icy badd ie a ot ee 161-164 VOT am baa aa a 34 longevity of stages, maximum......-..- 71 males mating with females of Dermacen- tor variabilis and Margaropus annula- oe dee oe ee ene ie ene Saba ey 164 Waren MAMAN ie si she i 2et. 4.2 2k. 158 aymple, Ceseriptive.:2)..02-.- 222.4 --: 159 Precermrarey. 2 foe ee at 163 periods in life history, maximum and (MS ee Soo fe 2 ot kee 70 rabbit. (See Dermacentor parumapertus marginatus. ) wanes a, adearmumave 2212022 2 2 oh beset sence te. 190 A 0 ies a ag es Daa een a -195-196 DOMtOr Arieieimerer rs eee! ois o ce sokke. 197 BTS Lapse SS LN A il ap anc a ee ee a 197 tear ve 2a Get) Veo 0 sal ee a oe 190-191 Gistripa tion, ema puis) Oe oo ca eee a setae 191 Penal w worry America: \o.0.. 002. 2525.2- 22 pconemmienmponiamrets te 82) ic2° Fh. s le. Sse 197 RD Pog 6 OR sae ales oe ae ee a ae ae er 191 LU on aes ele mere go eae ees 192-193 aes depantiond | number srs 200. . s eo. de LS 33 female mating with male Dermacentor parumapertus MMRNNERES TS 2208 eee IS Ee Oe Sc wie wa lee 164 ear Seances. tt Snes APY: ho ess Soe os 191 buat eect nine me ste Tie O is Se eee a lac oes 190-191 none eR or Nae eS Pe es oe oe 193-194 EE UE ens 3 ot Bay: Sa Bene i toned 0 abe aes ee a 196-197 No cas De ee 2 eee dl a ar 191-196 fonsevity of stases, marennm ~) 222. f. 2... Ss... -.. 2 7 male mating with female Dermacentor nitens..........-- 201 ce blgiic tie) AE et 3, al Tara bal cee oe oo a a 158 Dy gek ees 2 gl) Dee rote as A A 190 CSU Oia Se ae ea el A Sag Oe 194-195 periods in life history, maximum and minimum......-- 70 Postma Werte eae es Sastre sed... tee be. ee 37 Grin tin Tee Pe SOeR re eee eee Se 20 emuanity OCG, Weseripimyels s,s - 2520s. O els: Se... 165 vo da oO Ee Sg peea il pot ply ale Fas aa 176-179 pe ake oagkgi on (canary Sanat a ee ae a eed 35 SCHL itl Mises PEROT. <6. 2 ee cw eens 158
transmission of Rocky Mountain spotted fever... 111, 165, 180
ue eee de. sk. ou ca eh. enna s com ens 32 MOM ErOr, MNNEINOeNNees foe ee eee es cack ncaa ds 180-181
PMUEN PSO ees seas Gee ks acces tus ba veu ans 180 OMCININE VOOr tela. Otero eee ck ee. foe 165-166 Sisirioa iment pererapnieel Ao. ee 168
zonal, in North America, ...-ce--sserrsee 22
Do LIFE HISTORY OF NORTH AMERICAN TICKS.
Page Dermacentor venustus, economic importance... eee eae ee 180 ego, descnipityedts Ax. 2. Sele. bir aib iid a1 a ne ae 166 Tife histories asprakeet 84 Cons: 2 Rian eth ik eee a mane pet 168-169 evesrdeposited,, mgm ben 0.2 cc. Cee ee ce 33 erroneously reported as viviparous. .........-.-----.-- 24 host: relationplayis, sae aes Fee ee Se 166-168
investigations by Bureau of Entomology, Montana Agri-
cultural Experiment Station, and Bu- reau.-of ‘Biological Survey =: 20. Sees 13, 14 Ta OO SOG) es 5 eae) 2 ee a 20-21 lar vax Pesehip ive see cas ee acise oao St Slee ee es 165-166 laa, INCOR Ys) 62's Se ec Sale ote 169-171 lifecycle 228 supe. Ges Jet 179-180 PUI GOR Yi aps eect ye te 5 ots eon 0 Oe ey Oe 168-179 loComotiOns. 25.5. .0545enhebee cd sae eee 1 eee ee 33 longevity of stages, maximum): pe Re a AL mating habits. .5 22) oc eh enone or <a t he Be eee 29 molting doa bitsy 6.5 Siete Seth a ees ee ee 158 name used in early investigations for occidentalis... . - 182, 189 nymph, descriptive: 42-2 <1. 6 4es ee 165 periods in life history, maximum and minimum......-. 70 personnel connected with investigation............--- 166-167 Dappine against: brown.doe tickonc 2.542 Bae ee ees ee ee ae 111 Cayenne fi¢ks 3.0228. 5:0 Wee oe oe oh ee el ee 158 Gulf Coast: tieles 2. scucoacisn Lk gee Qh tee ae ee eee 142 Lone Star tiekee. hc. seit sep sees ata 2k 151 Pacific, Coast tH Ge so pes onc tt eo i ey pac i ihe 190 Rocky Mountaim: spotted-tever tickc- 46-2. .-5-.-22-55esee 181 LF Gl 4: eee cree Ree ee MEN MR RECIENTE eM Sh UE a 44 Dips against American. dog tick... 22250) 2-2 abe ca seh eee eee 197 Moc.aecidental host-ot cattle tick)... 3s ae ee 25 enemy. of Dermacentor. vanmavins wis ou) ashen e eee ae ee eee 197 host: of Anibiyommaaienrco nite ns. oe ee ee ee eee ee 143, 147, 148 COG CUTCW SC ape cs offers aI ye DES ee 152 RUA CU LOUD ae. a, es et ee ee ee ee is ee 139 PAL Der CULE UTD = 2.308 re ees aa oe a hee 124, 130, 136 Dermacentor occidentalis <2: 2 5< aise tte Seok oe oe oo eee 182 DURTQDUUIS =e (ee Ae 190, 191, 193, 194, 195-196; 19% VETUUSTUS eb ish crlg sora Aylate a ERN Oe Re ol Ue 166 BOWES MINGUS 22 ale. Aes, Boe ees a es ee ee Scan ea 82, 83, 88 SCOPRMUOTUS xn naldcs 2 Seed Se eg ep g hI NS are Pe Ree 77, 81 Margaropus annulatus australis. kee eee ote 2 eee TZ als Rhipicephalus sanquincus:4.2 22 sates sense 43, 102, 103, 108, 109, 110 prairie, hostof Tzodes kingtr .c0c25. <505. anes oe A ieee ne ee eee 83 Donkey (see also Ass and Burro).
5 host, of Amblyommaienjenmenseey oa 9 ae a ee es eee eee 157 Dromedary, host of Rhipicephalus sanguimeus.. 225 22 kao oe ce ees Dryness in control of Dermacentor parumapertus marginatus........----------- 165
Gi@KB 2 Soe ie yp ea yt 41-42 Duck, host of Argasimintatus:.<..2.5.2522) 32 See Nee eee eee ee 47 Berets, enemies.of ticks... 2.52 «20-4. 6 28a5 555ee eo eee eee 43 Hlephant, host of ticks s/s). (ce sae 4h Be ne are ree 43
Euphagus cyanocephalus (see also Blackbird, Brewer’s).
INDEX. 225
Page.
Pa phagua eyanocephalus, enemy of ticks. 6.20 cdss as cseecdcanccescaesesnsioe 42 Eutamias luteiventris, host of Dermacentor venustus..........----+--+-+-+------ 166 quadrivittatus umbrinus, host of Dermacentor venustus........-------- 166 Excretions during engorgement by Dermacentor...............----.---.+--- 158-159 a ee Se re 202
Felis hippolestes aztecus, host of Amblyomma cajennense......---------+++++++- 152 Dermacentor wertabilis sisi - 2a \ssiattale> 20 ons woo 191
Bana Noel Of Tredcs BCC PULATIS. 6 eit agile a ec ec esa ne edness 77
Fever, African coast, of cattle, transmission by five species of Rhipicephalus.. 102 biliary, of horses, mules, and donkeys, transmission by a species of
RENE NREN ae ie 8 aes i PO Mae aa ss et ons dn oe soot neces 102
human tick, transmission by Ornithodoros moubata..........-..-..---- 61
Rocky Mountain spotted, transmission by Dermacentor venustus.. 111, 165, 180
splenetic, in bovines, caused by Anaplasma transmitted by Margaropus. 111
Piroplasma transmitted by Margaropus. 111
Ca 6 SE ee 2 ee 44 Wilare michel, bibliographic reterence. -- 26 4. j252-25.)..-.--...-..------- 213
Pomme, Wimiiorraniic reierenees cae. yh 2. 2+ 22-2 ss 217 PbOn) eiitiany BIDMO CHE Lek = 2 ee eee eee oe ee ee 69 Pleas, accidental or temporary hosts thereof. ....-.....-.0:.....-........-..-- 25
Fly, screw-worm. (See Chrysomyia macellaria.) Fowls (see also Chickens and Poultry).
NIE Gl Ale MAM. eo a ee ee Ss ee 60
Go A ay phd De Ea Se ee 42
in Ces COIN RAT osi seen) 2 2.2 2 oe ese ++ ses 46
a Te eG TOW NOM). eee degrees ~< so a ee se ee 61
ES ee ee ee 45-46
eae, HOU Os AINDISOMING GINETCUNIIM. 2... 25. 2 - = -wienens tewacie.--------- 143
ES BSS ae eee See eee 136
rene RNR WR ah SS neh Si ek eae seek 191
Pee CCM DUES ROTM ROU oot ai i oS oh ahi Nowe alee cid + des os 20's 103
ORE EIS tle 1 Spee el pees a ae TT ey 0 ee oa i 46
Pe ee Eat oe Saja eek sans oh ew on cee re’ 47
POR ON enn fia 2h oko kek wad ose wie a coe os wi 46
aed, Moss Gt Ambijomimna Gmencantm. - 2. .-cans- ~~ << - ose ne peewee se ewen 143
AI PR MaMa Sa ek be we ale SOS 152
MIN te ee ew oh new akin 136
nt MET COUR Re ti. Sas ln aig enn we 198
Oe 166, 167, 178
Sern nrh its UR ee ie fs US Wis «oe oe a wins detec ee 112
OCS. 220 o. 5 it 6 waneGk aa nance 117
NURI NUNIT AA UMAR ORE oe oe oe hs wae win'n cnn dade cee munscaswe 103
MapUnisin, HOeb OL DeraCEnIOT VENAIIUS. < oni... 5 oc. ee cece ce eee nee 166 Gopher, pocket. (See Thomomys clustus ocius and Thomomys fuscus.)
ge a a, a ee ro 19
indirectly produced by Amblyomma maculatum.. 141
“‘Gotch” in donkeys indirectly produced by Amblyomma americanum.......-. 150
Grackle, boat-tailed. (See Megaquiscalus major.) bronzed. (See Quéscalus quiscula xneus.) great-tailed. (See Megaquiscalus major macrourus and Jackdaw.) tinkling. (See Quiscalus crasstrostris.) Guinea pig, host of Amblyomma cajennense..........-.---------+++++++++--- 155, 156 ney ok Lalas dalncénleceunegatae 47
21448°—Bull. 106—12——15
226 LIFE HISTORY OF NORTH AMERICAN TICKS.
Page.
Guinea pig, host of Dermacentor occidentalis. .............----.---- 181, 185, 186, 187 parumapertus marginatus. ...------.00 159, 162, 163
venistus. 22 2. 167, 170, 171, 173; 175, 176, 178, 179
Haemaphysatlis teports=palustris 2.) Ss. 0 ese a Doe eee ae 99
Le Ges BiG OR ood oe PSR LE SN ete 83, 86, 87 Heemaphysalis, adaptations of habats sos: Soe ee ee 28 chordeilis, adult, descriptive...-..- - 2 ae estes aS Se ar ent aaa 97 life-history s: 20 RO, See ee ee ee 100-101
bibliographic references ce. SALT ee 208
control artinel ees SARS oe 102
natural: sep cedt os ke ces ga sata Selle 102
descriptive ores 8) RAO eae ee ee oF distribution, geopraphical shee eee 98
zonal, in North America............... 22
Cconomiemmporance.. 2.65.54 -Se5 Somes eee 101-102
ese, life: history:..55¢ 242 esses SRR Oe 98
host relationship..22Y20.05 {Oar Ra Lhe cea Se
larva, descriptivertyis (Gy Ae te Ca Gee 97
life history «2. <<y.0.40s4 SOP ee ee 98-99
life-ey cles ccc .fs SLE 0, Se 101
history eth. Pt, Gees, 2 se ee 98-101
longevity of stages, maximum.......-...------.....- 71
molting: habits..<.32) 4.0 See A ae ee 89
nymph, descriptive. ces: .tiae. sect ee on Dee ee 97
life history:-:2'2 F208. 826| Bee ae eee 99-100
parasite of, turkeys. - 222.0511. DYS 4. we ane 89
periods in life history, maximum and minimum..... 70
peneral account...22.esere sc Spee Se A Bee ee eee 89 leachi, agent in transmission of canine piroplasmosis......-...- 89, 110 moltine habits, 2225538 ee ee ee ee 89 leporis-palustris, adaptations of Rena USES REA SE ees 3a ae 27 adult; descriptive i522. 2.222 fee eee 89
life ‘historysee uss eee ste. Sees 95
control, naturales. oe 2 ee Pn ee ae 96
déschiptives.2 2. et tse reese ane ee 89-90 distribution,-geoerapmical.. 2... 522s2355258 90
zonal, in North America.......- 22
economic importance ss. 4.--2. 9.6 25e2 heen 96
err <descripiives = co eta cheese ae ee eee 90
life history Tees ae hia ee eh ieee 90-92
eggs deposited, maximum... ...2.:--2..4024- 75
number. SMe ae ee ee 33
host ef Yzodiphaqus texans... 2 ).2) sate ee ee 43, 96 relationshipi.2.c8e0+ see see eo eee eee 25, 90
larva; descriptive orc 2085 cence 2 hae es eee 89-90
Te MISHORY O05 Secchi ooo he hea 92-93
1 Udy ea ie | nam ol i Ae ge eM 8 95-96
history. /-2224-. ang RES CS See eal
longevity of fee RAKIM: 2 ee Al
Moline Habits Skeet. Some. eee eee cere 89
nymph; descriptivess.s-8-22-- ckeeeee ee eee 89
Iie history... coe as eee eee 93-94
parasite ohrab bites. 42s-26ee-ee see yl ea 43
INDEX, 227
: Page. Hemaphysalis leporis-palusiris, periods in life history, maximum and minimum. 70 Omer Ng en a RE a old oak ees db cod anne me wes 89
i, ON INI are win ead de MES I agttals s dornidak 89
PII CS TL TD os ni. Seb ahs 2s OU EEE. AO. yt o£ 89
punctata, agent in transmission of bovine piroplasmosis. .-...- . as 89
PSE ag yi tal ee ee a 208, 211
SRNR ANNE aia ans ne ee tL Ae aR oS At ae 89
aug pacmine eels. american dor tick. .5.5-02-.o2-6 Bushs. b.eue. lel, co eoby Wid sicmesruies, Hit. AU. debs. ork tii atueoe ss 102
Dinee-lemeed tack sdbc.' feo eile eleb ns le oe 81
ae ee Pi es spe elu Shells ewheeee., 24058
eA ee eee Sr Obs SS 2 ot bee oso 142
Dame Bust at@Re 2 seee 4s). eats inl etl. yscias oor. 151
Rocky Mountain spotted-fever tick.................... 181
Meus. Seamer e eee 2h deere. arias Se oe eG. 44
“Hare, host of Hemaphysalis leporis-palustris........--..----------+-++-++2+---- 90 Tt Pia ES SARIN ake ie esd ch ba aes). votes fee oO. 103
ema MUNI, GCKE 2S a eee is Ladies w CU Sk Pte... ee see 16 Hawk, accidental host of Amblyomma tuberculatum.......-..---...---+------- 25 het. Anbiyoming Puberomatie.. dee! ak loges.ce din eee ds oan. 124
marsh, host of Hamaphysalis chordetlia.....2..2....2.22--+.+--++-------- 97
Heartwater of sheep, goats, and cattle, transmission by Amblyomma hebreum... 123 Heat in control of Dermacentor parumapertus marginatus.......-.-------------- 165
eae Bie int ahaa 5 a os RS A 88 APN, ieee a eee tat: dates, certs Sietsti, 2 vieeout do. 41-42 Heloderma suspectum, bibliographic reference.............---....--...-------- 218 Be sh ee nO OTGLE CIRETICONIIN <0 a annie oo ht EMR ORS HJ Ic len OR 143, 150 i NI it cde oe ag SEE BEL zt - Scry is Se eS MERE IRE a so ans 3c ELE WUE - - 223s; 191 SR Edel tet iad ain < od EEE En ae wos 166 ees MPs slates dove lita... ss. 62 Pore, Nos Of Ambiyomme americanum: 2. ie. .0- 60 esee....-..--.5.-.---- 143,148 RN on 2 AUS EMULE - 2 152, 157 LOU ee one ow EE USIISERO OIE . oes 136 DeCMRCENIOT TALES. own on on eno -= 1. YS 033. S ¥97, 198, 199, 208, 204 BERIT eae eee +. HO Fae Spey 2250). 2. ee ss 182 PPCUUE oo ea in EMS JOUER sc ane 191 i ie) Oe i i aaa Tei ehe . e 166 Pe TIONG ooo ore wn estas in gn o ores SEE RA os ink San dene 77 TE TRIM cole scgeninnis eiix wie pigans 6 EE Does 2 46% 112 ESS ee et ee 117,118 UN BOOTOS MANTIS... a copa eee fees Joos erugiel 2c... 52 eet DUCRNCIACS SAR GUCRCUG nna SS Dy Cis TYR wa aes 103 Humidity. (See Rainfall and Dryness.) Hunterellus hookeri, bibliographic reference..............-..------------++---- 214 parasite of Rhipicephalus sanguineus.........-.--- 43, 110-111, 165 Dermacentor parumapertus marginatus.......2.. 165 reared from ticks in Portuguese East Africa............. 110-111 Hyalomma xgyptium, detachment after death of host ..................-.----- 72 Soot Gorn Numi her. gis. vege kG) oa Fe. SAE... <0 32 monk tins Tigmetenes esos. wot okeGS. eles tke. cae 25 impressum, host relationship. .........-- tis cine. 25-26
venustum= Amblyomma variegatum...........--+--------------- 20,32, 54
228 LIFE HISTORY OF NORTH AMERICAN TICKS.
Page.
Hylocichla guttata nana, enemy of Dermacentor occidentalis...............----- 190
TICKS. cic 94 4.5 eye Re a ee Be 43
iHypostome of ticks, description,..5... 4-2 s2ccn Seyeeln ee ee a a 16
Feuana, host.of Amblyomma dissumiles_.2 0.4 Oe ees 131
Inflammation caused by Amblyomma americanum.................----------- 150
Dermacentor occidentalis aie 5e 0 Be. ke dos es 189
Isolation in; comtrol of fowl. ticks... 223% ack eA ee he oe 61
Ixodes, adaptationsiof structure s.4....co008 ee OE Se eee 28
xqualis, distribution, zonal, jn North Amerciatve: 78 22222. ee 22
affinis, wrong determination of Ixodes scapularis..............--.----- 77
angustus; distribution, zonal, in, North Amercateeeeu _.<) 3. yee 22
woodi, distribution, zonal, in North America.-.............-.--. py
arcticus, distribution, zonal, in North American’. 22.5502... ee 22
banksi, distribution; zonal, in North Americas). Jc. 20.2 ee ee 22
brunneus, distribution, zonal, in North America.................-.-.-- 22 California. (See Ixodes californicus.)
californicus an important species of genus in United States............ 76
distribution, zonal, im _North.Ameries. 2... 85050 so eee 22
mating. habitssa:isee OA eee I ee 30
cookei, distribution, zonal, in North America.............--.......... 22
rugosus, distribution, zonal, in North America.........-..-.-..- 22
dentatus, distribution, zonal, in North America........................ 22
diversifossus, distribution, zonal, in North America........-....------- 22
general account......0<scirwiaimerreceaan neers aia sae eee eee Sere 76
hexagonus, distribution, zonal, in North America....-......----.-..---- 22
mating habits... .'1 3297 e ks ae ee a Se 30
king?, adult, descriptive... .2-<..<.2sd ote nee en eee eee 82
lite history cc ccspe coe < cun kk ene ce ee eee 87-88
control, matutal 2 sccec.s2-2 c+ erro as Oe Re ee oe 88
CeSCriptivie.....- occas eaeees ae 2 ep ete oe ees ba oe ee ee 82
distribution, ceorraphical.... «.<e. .1 AS ee So eee 83
zonal, in North, Anteriea ys: i), aero el eee 22
economic. Importance. 5.2L. c ce «Sc 6 oe Mere serene 88
Cop: MescriphiVes co 2 ance anna c ONE MNS 2 nr ar 2 aera 82
Rife IIStOT yy. soo 53. no nc cgrain Sloe ee SE coe arate 83-85
esgs deposited, number: —. .. 1. See nese set <2 - = oe os eee Jo
hiost:relationsbhip ss...) cqossi oe se ee ee See 82-83
Jarva, descriptive. i225 22532. ee | ee ee eee 82
life history 22.4 «32.2 420k ems as oe ee Se Be eee 85-86
Vike CY Clee x's aise min oldie ene te erence OS SE Re ae a a 88
ISEGL Ys oo oe ats 5 I ae ee ee ee eee 83-88
longevity of stages, maximum... .2820ns Ge saseece reenter 71
nymph, descriptive.2.242-...--oS) SIs Ca Oe eae 82
life history...) ’< |... L SeePOoess was ee Dee ee eee 86-87
periods in life history, maximum and minimum.............--- 70
marxzi, distribution, zonal, in North America..........J..-.-...-:-.--- 22
, » oviposition) :firstidesesintiom afigeceessyier ak. so ee eer 73
pilosus, bibliopraphiereierence sl 2 2578 222 Ae tee es 2 ee 210
mating habits....visi 5.) Se! eee See ee ok eee 30
studies on ‘the species..025 Ua! Peg eee AA oe 76
pratt, distribution, zonal, mn North Ameriese sips eee (27 ee oe 22
reduwus, bibliographic referencest cues ous. 1 SOeReaes eee. 2 211, 214
ricinus, agent in transmission of bovine piroplasmosis...............--- 76, 81
INDEX. 229
Page.
pease rics, bibliographic referenice.')5. 50. is... 25 5252----2222- aed 205, 212, 213
rir SRN toe 2: : > Bad ace wat} Ine been er numed- be 30 oviposition, first description of process.................-.----- 7
ee ee ae, a ee ae 31
UCkuee Te SCI 8 Sekt ee a > bn cnt Be tad 20, 76
ge Ro ee i oe a are 76
See 5 Sa a a ee eter Eee 80-81
an important species of genus in United States..........-- 76
we ek) an | ET, ee eee, i oe a se 81
Ct ae ee ee ae ee: er oe oe ae 81
Pe ne yt Me ES, I eer en) el a 76-77
ee or | 77
momeak. a Dirk Avineetica. 6s oe 22
ee Oe ee coe ee 81
Og EE SET SE RSS DE ee 77
Oe ee, eae ae ae 77-78
oc Be Oi oe a ee a . ae 33
se pan oy a ee a a a i 77
eee | a ee ee eee ae nee ny cae 77
aie Ra ace ir Say 2 bo oc ote 3 79
eR a ae ty Dips Pd, Spe ee ee eee ee ee 81
SII ete eke eR casas. Sulack Baik he mate 77-81
lonpeyity Of niapes, Wax 2k. es 2 ts 71
eg EES ae a ae on See Se eee eee eee 29, 30
not to be confounded with Jvodes ricinus.......-....-.-.--- 20
Te ee On SE ee rs ae 77
NC AORN Sh Be ee A we 5 oe es 7980
periods in life history, maximum and minimum........... 70
Fe od pa en, Sn, Oe ape eae ea 20
sculptus, distribution, zonal, in North America. .........--....--.--- 23
teranus, distribution, zonal, in North America.....................-.-- 23
RE a a en ae ae 75-76
cp a ae oe a ee ee a ee 69-76
2. Be ee Ee a ee ee ee fe a ae ee 73
cmemens Weninees Ont Kinet Garey Tam tie 8 ob arp ls w . - =< ss - = owe 69 | es ee Beep Erect) SUES A > eT as nt Pee eee rr 7
SS SS SS eee on ee | eee ne ee 71
SIT LL i eae ee 74-75
UE I la aE Ad Bi ad eit wha in ape ks mia a eA ws we 8 71-72 Oe en oe nay aera Seals Sa obey ee a oe 7
Ixodiphagus teranus, parasite of Hemaphysalis leporis-palustris......-.--.-.....-- 43, 96
“Jackdaw” (see also Megaquiscalus major macrourus). Baie OF Timm phpealis CROTEOMNG. oh A nesigics = 6 aninin's ss. = 50> << 202 97
gg ee ee ere 90 NB ge 8 ee 24 ee ge ae FEE IDE Se Ry ar ay a 61 spinose ear tick—a dangerous remedy..............---.-.--- 69 ee Te i ee | te Br nn ce ee a a 204 metectzve seem bind tick). 40s ces. ssc. ....--....- 102
Killdeer (see also Oxyechus vociferus). SO ee 97
Kingbird. (See Tyrannus tyrannus.)
230 LIFE HISTORY OF NORTH AMERICAN TICKS.
Babtanr of ticks: 2: > 2224252 Saeko SS i Sk, I Oe 16 Eard and ‘kerosene against Cayenne: tick = 2-5 22sss sass eee Soe 157 tro PICA WOE TLC Ls IONS pens Me ENE 204 inelectiveaza mat: bird tele Sas eer see ee ee eee 102 Lark, field, host of Hemaphysalis leporis-palustris..........------++++--+++-+-- 90 Laudanum and sweet oil against spinose ear tick. .........----.---.--------- 69 Leporide, hosts of Dermacentor parumapertus marginatus.......-.-..---------- 25 Hemaphiysales (eporis-palgsty tse eee wae se es ee oer ie 25 Lepus aquaticus,; host ot Dermacentor -wartabilis = se NS ee 191 bairdi,- host of Dermacentor Venastuss: 5 easier fe ae 166 Hemaphysalis teports-patestris: =. 0 et tee oo ae 96 palustris. (See Sylvilagus palustris.) cuniculus domesticus (see also Rabbit). host. of Margaropus annulatus australis...........-. 117 Lion, Mexican. (See Felis hippolestes aztecus.) Lizards, enemies of Margaropus annulatus australis.........--..-....---+2224- 122 Magpie; host'of Hamaphysatis leports-palusivis.- 820. wee nee ne ne cee 90 Maminails: hosts’of Amgas:s 2220 oc cen oe ea ate See et ee ney en 46 Man, acerentah host ci tab bu eae eee ee ee aes Za Eikipicephalis sanpuiis 2 Noe ek ee 103 attachment by Margaropus annulatus rare:.-.22..222.122...%2-2.------- Lae host of Amblyomma amertearninu st sss=s2 soe eee eo SE Mone RE 143, 150 COVENMENSES a eee ee anne eh ee eee ae etd 152 CisDer CULMbUNER <2 SR Ea eee abr Pe Mele Rete ar! cers cee 136 Dermacentor CCACTAMIIS: rts es Ne ee ere i eae 182, 189 DAT UIMNGPCILUS*MOATGULOLUS 1F fone se Ne Pee Oe Ss oe 159° VUTUADTIS 3 FIR EAA RRR Ne ees CORN orth a cieenn ee 191, 197 Margaropus arinilacus GUsir gies «Nes PEE I eh 117, 122 GCA OT ALS 6 I BOO es Fae J) a Ornrihodores Megniniee te sae eA. eh eS NEE eee ee 62, 69 Mandibles of tickses opens ee 2 eae ae ee rs Lae ed teres eee 16 Meandibultr sheaths ‘of ticks. ions ss5Sete see eet ees tect ee seek eee 16 Marearopus; adaptations obhabits. (724 s2sshee 2s sees ae See ee pee es ea 26 annulatus (see also Tick, cattle, and Boophilus anmulatus). adaptations of daabits: ste Pee een) Fant Sega eo 28 adult; Gescriptivies:.chs2 ates keene o ents Leder G 111 late: history... Seb eens eee ndings Ange OTe 115-116 . agent in transmission of Piroplasma and Anaplasma, which cause splenetic fever in bovines.....-.-......- 111 bibliographic reterence sso 3 2455 ttiret se coe oe 208 Gan bal srr FAY A Pe EI Rg 4 eat ete 32 control, arrprinera ls See Sb) Bean ees a Aenee gerelee caly ae 117 OLAV O cee ig UE ig Ree ita til Naa oh ch eda na Geseriplrver we wee roe we ee tes ee ate Aneel a 111-112 distribution eeorraphicalss Oe ee ees Te. eee 112 zonal im ‘North-America.’” S22). ese ee 21,23 early investigations by Bureau of Entomology..-.-..... 13 ECONOMIC IM POtaNnce.. se eee ee, TES FOB hig ege, descriptive: = 52h eres see eet saci e earner seme 112 Life “history 215° Pa POOR RMIT os) Ao 112-115 eggs deposited, nuniber: 1:2) wee hie ew eae ee 33
female mating with male Dermacentor parumapertus MATOINGLUS: «isc 21 53 5 RE a eS 164
INDEX. 231
Page Margaropus annulatus, first studies of life history and habits................... 20 pra et a or a oe een | ee a 112 ieee, mececptavetns cidies Tel does... nc zeee 112 i » dala OP rey as agg OF Sn Cod ny a 115 TA CGO rd Fo i si oe 202 hous care Was ceeet 116 hidtoey) . teas Sebeseuzen th Jolerd. vole sivetes 112-116 longevity of stages, maximum...........-.-.........- 71 nies Habe i ss.6- oda EMR OOS, Lee LA 31 RIO eae See SS DS TOPE ST Ost ea cyst 25, 70 ee eh ei de a 111-112 inie Aialapeaaete s POMBO OSIIIS) Ls ee cle 115 oviposition, published descriptions of process.........- 73 periods in life history, maximum and minimum... .... 70 pe Tes Ot Net oA eye oe ae 42 [earns teeter ae Uae. 28 2. 55. on 2 41 australis (see also Boophilus australis). As, Greeipbive -...saterrent 2eg2d. 52 sds eek 117 eg Se Lt 120-122 agent in transmission of Piroplasma and Anaplasma, which cause splenetic fever in ee sOhsy Akt sos sae ernss Sew. J. 111 conttoh-arahicw' 03 as seS es DESL Seek 123 faba ooo Sa ee NG SEER 122 deteemiiiperiss: lesSaurls cc Rares 117 distribution, geographical.............---..--- 118 zonal, in North America.........- 23 peonnmicamipotinncesnit Warts iss). ..3 565.5. 122 eae i deacmptines auth ae seerest os. 2. 2 117 Hise ss ce ee 2 BR... 5 118-119 eggs deposited, number...--.-.....-.---...-- 33 female mating with male Amblyomma ameri- TER RI. A. Sees. SO OSU Mee 149 hock weietwmeitine septic Sea - ce ed: 117-118 larva, Generiniiwe ite ve utius 1 fe Uy ie fs Tec es 117 life Tagmorgerwetiere..- .-- ...-%-...-- 119-120 MRC cca tees PREIS SIPANIWSOL ce. 52. 122 ey ee) eee 118-122 longevity of stages, maximum...........-...-- 71 male mating with female Dermacentor nitens.. 201 molting bahite.....Wsesget Aloe ds 5640S... 25s. 70 nyeeph, deoseriptivessitese sos fond. ecko. 117 ile Eateie aie sO. S32 sod. Hawes 120 periods in life history, maximum and mini- oS ees eS ene re 70 prey of Crotophaga sulcirostris.....-....-.----- 42 gtdien af the apecies. 20 2508 . 2 Cs Te TAR es 20, 21 microplus= Margaropus annulatus austravis, according to PININ nca ayant s dda oe RON COU Sn we ices 118 decoloratus, agent in transmission of Spirochxta theileri, which causes disease of cattle in South Africa...........-. 111 detachment after death of host................-.----- 72 ontie- diadine... jell, bi sat a ad Wc Se yeek ~~. ..5- 20
Se ee ear ig ae 118
239 LIFE HISTORY OF NORTH AMERICAN TICKS.
Pp Margaropus.decotoratus, mating habits:/4. 22. We ae “30 parasite of mance... edie Saeed eS 117 used by Theiler in experiment on horse............. 18-19 generabaccouib.< <is 226 [Ses Sa, 2 ck ce oe eee TRE Marmot. (See Marmota flaviventer.) Marmota flaviventer, host of Dermacentor venustus...........--...2----------- 166 DOS MECRG B32 es BIO RIN oS os eo aon Se 82, 83 Meadowlark (see also Sturnella magna). ¢ host of Amblyomma tuberculatum. 222.22. 202J005..-2 20222222 136, 139 AP GAS TUIMIGIUS 555 FS SOI CINE NE A 47 Hemanhysatss chordethisn Nea. oo Re 97, 99, 102 leperts=piclirsipis sutslegeto 2 wes 25.2 e 90, 96 Megaquiscalus major; enemy ofitiekson. oregon! scl a) eee... wo oe 42 macrourus (see also ‘‘ Jackdaw’’) enemy of dickeut tin wile oo sk 42 “Miana bug,’’ colloquial name for Argas miniatus in Persia.................-- 47 Mice; enemies of Argus miniaies. <- erie Giesean). TUE ok es ee 60 Margaropusanneilaine @isirats. 20012) 2 oa ee ee 122 hosts: atiAnges mitnahise: Jos) 62send: ce lee ee cS.) ie Ss tae ge 47 Microtus modestus, host of Dermacentor venustus..........-..--..-..--------- 166 nanus canescens, host of Dermacentor venustus....-....--------------- 166 Pink, host.of Jrodes bingt..z.cscseelses2 mene For en 83 Walothrus. ater, enemy of taeks: uss. so) eines SO ee ee ee 42 Monomorium minimum, enemy of Dermacentor venustus.....-...------+------- 180 Mopping against: black-lesgeed ifthe Lar ee See ae Se 81 Cayertnd tek..25-leteeuiteAl us tee See 158 Gulf. Const tiekssa.caceteth the) pees. eee es 142 Lone Star teks. sec ihteeneely ees: oles Soo ue ie Bee 151 Pacific Coast tick. .cseeseateirt 2 sees F ees Ao ee 190 Mouse, gray meadow. (See Microtus nanus canescens.) jumping. (See Zapus princeps.) large meadow. (See Microtus modestus.) white-footed. (See Peromyscus maniculatus artemisiz.) Mule, host of Amblyomma.americaaum:tesieeeise Ses ee Sees eb ess =k ee oe 143 COGENTIERSCON SED ANE) GR Sa Sieh 2 eC es 152, 157 Dermacentor WHENSs. 326. 5. AR 198, 199, 203, 204 ocprdentalis xcs. 27 tame 5 aii: aSeele od Ane eee oes See 182 DOMUBTUS ceteris ago Se NCE ees ay ee ae ho: eye Sie oe oie 166 Margaropus annulatesi ise Se-63s: ba. oe SEER. 2 2 Fee ei 112 Ornithodoros meg aint sci beEiei e ache e 62 Neotoma cinerea, host of Dermacentor’ venmstus foee25- <= sees 5-2-2 5 166 Nichthawk, host of Haemaphysalisehordeths =... 202 te ee ee ee ene 97 Ochotona princeps, host of Dermacentor venustus......-.-.--------------------- 166 Jredes BANG). 60d - se TADS ee ee oe 82 Odocoileus toltecus, host of Amblyomma cajennense......-.--.----------------- 152 Odontocelus americanus, host of Margaropus annulatus ......----------------- 112 Opossum, host: of Dermacentor variabilis.... 2+ - 2-2 2226-2 date 2-2 -= 2-2 -=- 191, 195 Trodes:scapulanissc3.0% cea: | eee ae Se 77 Opsicetus personatus= Reduvius personatus.......-.-------+---2-22 2222022 - ee 42 Ornithodoros, brief account of genus...--+-+-+++-----+++--+--- ees! See: 61 coriaceus, distribution, zonal, in North America.....----------- 23 megnini, adaptations of habit........--.-.-------------------- 27, 28
adult; descriptive. .- -s4o5e0.eq ah asset see ae 62
INDEX. 233
Page Ornithodoros megnint, adult, life history.........-.........2.0-----2200--0-- 66 Iniliopraniic references... 2205 5322565556220 5l 205k 213 conteoljpartiGetelis iiss vescday ress ss 2352 APL 69 PG nine AON CSOD A Ae PE 69 MEME OMe Beery 3s PIII: oe a 8 62 desea ioe = STPTE PISS FSS ST 34 distribution, geographical. . Poe RE eet eee zonal, in North Maeda SAsye, (ZOE 2A 23 eeonamic importance. .s.-8 UPS 927 F. 2 A ALL. 68-69 i, MORIN iret as soo 5 or ses ce PEST ICE 62 Oe ee ee 3p MS a ee CAMs Oe 64 eggs deposited, number. .................---.--------- 33 PRIN ih ee EOS US ER SOD es 45 iideh celedmminagndi? 251 sbi So Ss SINE we. 62 RE, INE a 85 Se Pd JOM OSM. = .' 62 in pies ernest atoms sk oer Tet 2S. 65 iin gycie.. eerie be Boles a deem se! . 2. 68 Ee Be ee ee 45 inating: hahthedenuse D). 29) reste e018 v0 8882 2. Sos 29, 66 eg ee ee 25 pyanpin Mecrripliver. 5.¢0.cusesss2tett Pte. 2 62 life histonpscesses ol 2st. oor... Dk OA jparaatie periods. +. 2. ose 1 bes.c2 28 cs. 67-68 rearing, methods... ..-.--..- 22. RSet Poa) fe ee. 39 en ne, er emer eye See hl ered como ee a: 31 sunmiosed: spxmeh enablers] ude: 42 ho iutoei a 2A 66 moubata, agent in transmission of human tick fever.........._- 61 bibliographic reference..............-------------- 211, 214 ae BS eo ego: foe’ 2 uc ck 45 = ie ier So oe 30 savignyi, experiment by Lounsbury..-...........-.------------- 60 eR a ee ee et oe. ee. OE 45 observations on the species. .........-..-.------------ 21 Prema ce ese Gates 02s... 2 2 see 31 SITES Tic peta es oc Soe 2. 2s ees a 66 CI IUMTT IN cigs Sa PEABO Sas Se LZR... 30 talaje, developmental peculiarities.....-..... ve doe cco 24 distribution, zonal, in North America.................-- 23 pocreligWtan pus adeenhguwewe ee ioentrets dress. Je... 31 settee. CAMMIDOIIOIES «5 anc 54 ERPS. See ks. 22-2. 2.8 32 distribution, zonal, in North America..........-..-..-.-- 23 SOON 1.35 inne See. Sees din. Heed. - 31 eg Ee Ee a 47
Owl, accidental host of Amblyomma tuberculatum...........---.--.----------- 25 bieksk Bre bipouma tuherceiattmissc cu cates es Sots cde. cs.) Ox (see also Bull, Bovine, and Cattle).
ee eee) ee 152 SGOT BU ie was oe = |= Dee. 22 2. Se 198
_ variabilis. Aeeb eta denw eae. ieee... 2... BLESS
Rhinicephotus sangiainenes: oS evades. au iedicess cewicrenewl 2... 2. 103
Oxpecker. (See Buphaga africanus.)
234 LIFE HISTORY OF NORTH AMERICAN TICKS.
Page
Onzyechus vocferus; enemy of tieks:..25-. 2524. sae eee ee a ee Been 43
alps of ticks... 2... 7 24ees oe Ses eines se eee A ae 16
Parasites of ticks. ... ~-::-..)5¢ 233 Baap aa SE ee ce i 7 ee 43-44
Peecary, host of Amblyomma americanum... 2. be ee ey ee ee 143
CO CNNENSE 55. <1 k ee EM aae y.ah Nee eeea 152
Perodipus richardsont, host: of Jvodes kingt:2) 55. .aaseees eee - 2 SY. Soke 83
Peromyscus maniculatus artemisiz, host of Dermacentor venustus.. t tmatitee cele
Petroleum, crude, against fowladk. 2: o4- Jagoes 22 552k ees Sere ry 61
Phrynosoma cornutum, experimente: sz 2veisouc aie Sens ae 129
Piveon, host of Areas: s25 Jue ees i, Dep eee ei A ee ee 46
Pika. (See Ochotona princeps.)
Piroplasma bigeminum, transmission by Margaropus annulatus australis....... 122 comis; bibliographic reference... 0.2 cece eteeee~ o ~ 22.1 206 causing splenetic fever in ane transmission by Nereeronas) Bere os ts parasites of G1Cks. <<. 24/3556 Nee es Bear oe ei 44 parvum, bibliographic references dite beck ou Jone! 35 So ees transmission by species of Margaropus.........-..........--.---- 1:
Piroplasmosis, bovine, transmission by Hxemaphysalis punctata.........----.-- 89
Iaodes nici sreetes eo 2s Lt ee: 20, 76, 81 canine, transmission by Hemaphysalts leachi................---- 89, 110
Rhipicephalus sanguineus in old world. 102,110 ovine, transmission by a species of Rhipicephalus.............. 102 Plover, upland. (See Bartramia longicauda.) Poultry (see also Chickens and Fowls).
hosts'o£ Argas mintatus: 255.2 (oc BONS ie RE Sp tee ee Se 47 Predaceous enemiesiof tickae Je: 1c oo eee ee ice a eee: - Soe oe ee 42-43 Protective adaptations in the genus Dermacentor...............----------+---- 158
of habia: tieks: cetera. 24 JU BOGE) 28-29
Quail, host of Amblyomma tuberculatum.........--.-------- B eens ati Seer eee 136 Hemaphysalis chordeis nee eae es ica PE ly See ie ee 97, 102 leporis=palhiisivas: . so A ek a 90, 94, 96
Teodes scapularis: <0. Ire SR SSS EERE (ARO oe 77
Quarantine invcontrol of tacks ise. 2 ea EE eS ei oes 44 Quiscalus crassirostris, enemy of Amblyomma cajennense.......--------------- 157 Margaropus annulatus australis.......-..----- 122
HCKSi 4 euicic crt TORR MIM EY 3 oa See 42
quiiscula. eneus, enemy Of TICKS. cnc ake eee eee 42
Rabbit, cottontail, host of Dermacentor parumapertus marginatus.......------- 159 Hemaphysalis leporis-palustris..........-----+----+ 96
enemy of Dermacentor :parumapertus marginatus........--------+----- 165 MORUUSUNS) OIA, pci, 2 RIOT ERIE LN i Se he 180
Haemepliysahs léporis-palustris: . 22269 ee 2s 2 ee 96
host’of Amblyomma americanwitces: 292 eee 146, 147, 148 MACKIE cca 2 teh eee aes 139
Cuber culate ON A ES IOS TETAS 124
Dermacentor occ.dentaliss ae ES LE: 181, 182, 186, 187
parumapertus marginatus.....------ 159, 161, 163, 164, 165
VOTUADWIS ER: Ss 5 RARE TDI 191, 195
DOAUSTUS. De Ee 166, 267,970 0.702 W738) 875) 276, 178; 179
Hemaphysalis leporis-palustris......---------- 43, 90, 93, 94, 95, 96, 99
Teodes Mingtec 2 oo 6S PSP eS Ee Oe a 83, 86
Margaropus annulatus australis... .. PRUs Sia eer A
INDEX. ; 235
Page Rabbit, jack, host of Amblyomma tuberculatum.........-.....---+-.--+---+--++- 136 A A at POETIC EGE onc ons ce cna oe 47 Dermacentor parumapertus marginatus.......-..-.-------- 159 Hamaphyealis leporis-patusirvis..o0 020. .-.-.------------- 96 snowshoe. (See Lepus bairdi.) swamp. (See Lepus aquaticus.) Haccoon, host of Dermacentor gariabiliss 252.90. cette eee 191 Oo UE ON EON Bh Pe 0 Wes eg 2 oy oie a Ter ee ee 41 Pees memier al Argue eae NER oases SE SSIS SINGS: BPS eS POEL eee. 60 Tie, GE ar Gs MUNRO eka ke cee ENTAIL 47 kangaroo. (See Perodipus richardsoni.) wood (see also Neotoma cinerea). hors ae Prey mmatenier penistis oo ET. cnn 171 Beery tae, A ae a eee ee SE cee 37-41 inn precmnus Cmmmiy OF teks. Loh 2228S 2 - 42 Reptiles, hosts of Rhipicephalus sanguineus...........-------------+-------+---- 103 probable enemies of Hemaphysalis leporis-palustris.......-.-.-------- 96 Rhinoceros bird. (See Buphaga africanus.) aL eee Sere eee re PO FY BO See Sct oi 43 Rhipicephalus appendiculatus, mating habits................-.-.------2-+-+------- 30 bursa, adaptations of -habit...2..0) 202.2... 27 aa W ent amine ee ee te ee Sl sels 105 muohanp Hisbwne: 2222 552eete ee Se 25 ee Peemeae sani te eg Spek ne ween oon. a hie kk 29 eocrim, adaptations ef habit<2: 222220 -PP PTS. os 27 detachment after death of host........-........2.......- 72 ame gaiep rn cues er eS ee Se ee 7 imate Dalbaisisi ers SE eS 30 mobi erly Inshinlet 2 oes 25 PSO 25 pomeeebacwntace siesta le + NSS PSE AR oe Doeeh 102 sangumens; adaptations of abit... 22029222... 222... 27 neta, emerEpteves 2 scosecser ss! PETS |... see 103 life history... ee Seo ee agent in treniiniienioin oF canine oysieep tiivonas in old ORR re ee eS USSR 110 bibliographic reference.................-..--..--.- 213 Comin, irinaciade hs Pe Pe ee Se 111 rere ee LS SPE, OTM 110-111 demerntaves astern ee SSeS TP. distribution, geographical. SE ae ae ee 104-105 zonal, in North America.............. 23 cconcieah Sea ertane ss Na ET SR eG i er ee 103 iMeihaminr yp AwsGres (eet 2. SOE STO 105-106 gs deposited, piles 2 Recess 33 host of Hunterellus hookeri..............-.- 43, 110-111, 165 Ae ee yr ee 103 investigation of life history and habits............... 21
Sarva; eMC BAC EL. 08 Rife histor yor. 22a Sy Oe 2... 106-107
PU CI ink 5 i OR ER EL. CMS Py Pete eee Re 105-110
»
DE PONNS bode eridas PUD L aL oc k cau vec cceccuccavcn 34
236 LIFE HISTORY OF NORTH AMERICAN TICKS. Page Rhipicephalus sanguineus, longevity of stages, maximum..................-... 71 mating habits. os: scces02 ee BeOS 22 2 eledies 28 31 molting habitssoa canadian sete ae eek 75 nymph, escripthve.c4: ssh el eee ad 103 life history. cesses de eee: -aedewiove 107-108 parasite of dogs... 2: susssiekee seed Ga ganas 43 periods in life history, maximum and minimum..... 70 texanus==Rhipwephalus sanguineus......-...-0-+..620s0202---5- 102 Robin, host of Hamaphysalis leporis-palusiris. . 3... 2.-254ie sae seat e ee 90 Roost, tick-tree,. constructions .22-.) oe -ci5<ese bieeeeiie ss pe ee 61 Rotation (see also Starvation). system against Pacific Coast tick s.2- 2 Sees eee ee 190 fiekes 7. 2 Alay. dese eseeyeneeteeh ta ee oe 44 impractical against’Gayenne tick-2232 95.0. - Aiea Se 158 Lone: Star tick.<.».. e:bsit Gece ben Leelee Be 151 Sciurus hudsonicus richardsoni, host of Dermacentor venustus...........-.------- 166
Tpodes bitigtcvsJh. Ge ow icesa. Glhdadkwascnn 82 Screw-worm fly (see also Chrysomya macellaria). ovipositing in wounds caused by Dermacentor nitens......... 203, 204
Seutum of ticks, definition: < ..222) 2 1.222 Beeps eee SREE ee ee ee 16 Sheep, host of Amblyomma americanum... 22 esa Fo Se Se eet Seen 143 tubereulatuinges Sess. ee ee le kt ee 136, 140 Dermacentor occidentaliseoriss 3.02: cess d bowen: st Se ee 182 VENUSTNSE: og Ol be 2, he cep i ek ee ose 166 Trodes: scarp ilarts «<5 2202 sees, ea pon etal ic pli teloe weer cad 17,82 Margeropus- annulatist so. ites orate Seo A aie be ee ees 112 mistralissieke 26) eth rte en eee LT, 1s Ornithodoros megniniece: << 2535355 ae dee eebery 22 Bearers 62 Rhipicephalus sanguneus ccs 5. ek pad eG te ee ee 103 Skunk, host of Amblyomma americanum. 22 ccs <= soos cles daa oe 143 Dermacentor variabtlis: Dove Sack Matreeb ate: che ate hess ee 191 Teo des RAGE ono occa lee ey et ey Bi ee ae ene ee ote 82, 83 Solenopsis geminata. enemy- ot ticks:..).3 ae wat ahs ses toot eck see 42 Sparrow, host of Hemaphysalis leporis-palustris.......-.-..--+------------+---- 90 Sparrows, probable enemies of Hemaphysalis leporis-palustris.....-.-.--------- 96 Spermophile, ‘host of Jrodes hingt2 4. sp seeped eee eee 83 Spirocheta anserinum, parasite of geese, transmission by Argas miniatus......- 46 gallinarum, parasite of chickens, transmission by Argas miniatus.. . 46 parasites of ticks. : sos g5s ce cles See ee a ae 44
theileri, causing disease of cattle in South Africa, transmission by Margaro pus decolorgtuse sss teen ee he eee ee eee ee 11 Spirochetosis of fowls, transmission by Argas miniatus...............------ 45-46, 60 Te flerSs. mabe. La ik ee es 45-46 Spraying against brown doe: tick: ijt... oer eta Se ee by ticks: -...... Seen eeeeete | tte i ed ee 8 eee ae 44 Squirrel, fox, host of Dermacentor parumapertus marginatus............----- 159, 162 VaMAb UW Se Daas eee ie ii Nel eo iat 191 DOUG S, 3-1. cee mene eae gs Gate Ss 2 See Ru 175, 176
ground (see also Citeilus columbianus). host. of Dermacentor venustus 5.568 2325-22... oe SS ATA, L727; EG host of Amblyomma americanum... .. >) esa eas ee ee 143 : ‘Dermacentor: variabiliss: 759i) 2). mee eR) ee a ee, Se 195 VOTVUSTUS 5% 3055 - oa tee bed ie Rey a oe aes ae 173, 175, 176
INDEX. 237
Page. Squirrel, pine (see also Sciurus hudsonicus richardsoni). host ob Derasaeensor meme So. se OS. 2 ass 2s os 2% 171 Hemaphysalis leporis-palustris.........-.222+-+++----- 90 rock. (See Callospermophilus lateralis cinerascens. ) Ra. POCO“ REEMIMS 2 it tact ae ad Soha ooo hes otis nie ars vod OS Te ES SEE, 43 Starvation (see also Rotation). system against Australian cattle tick..............---..--.2....-: 123 Se PANE GEES 2S Soe oe oe 2 ISTE 204 impractical against Gulf Coast tick................ 142 Sturnella magna (see also Meadowlark). enemy of ticks. Ee nn ee eee, Se | ae ee 43 Swabbing against Rocky Mgintain peated: pe vertickes OS PL 2 2 181 Sweet oil and carbolic acid against spinose ear tick...-.................-.--- 69 chloroform against spinose ear tick........-........--..------ 69 landanum against spmose ear tick. ............-.0/i20i.0.2020. 69 Sylvilagus nuttalli, host of Dermacentor venustus .......-..-----------+------- 166 palustris, host of Hemaphysalis leporis-palustris......--......----- 90 Tangavius xneus involucratus, enemy of ticks.........-.-.-- Peas Eduet 42 Prd CORtTIN OL AORN abe coee ike Elie pee cee est. AED 41-44 aise S18 SLCe ee Ot BOC 4 eh Pet kes Lees ORE IE 35-36 Thomomys clusius ocius, host of Ivodes kingi........-...------------++--------- 82, 83 pesca, tet of Dermacentor gensustus? S02. OSS Ss ea os LOPS 166 Thrush, dwarf hermit. (See Hylocichla guttata nana.) host of Haemaphysalis leporis-palustris.............-------.--+.-++---- 90 mecbrarepuloneanas, 263, 22075. SEI P IOS, A Sees aie SECLE 77 Tick, American dog. (See Dermacentor variabilis. ) Australian cattle. (See Margaropus annulatus australis.) bird. (See Hemaphysalis chordeilis.) black-legged. (See Ixodes scapularis.) brown dog. (See Rhipicephalus sanguineus.) bull frog. (See Amblyomma dissimile.) cattle (see also Margaropus annulatus and Boophilus annulatus). omens weet A rthed Miabee noes oes oooh se 18 0 Ee ete Se a oe ee eT? CERT oe tag OF 34 er ee ees meee Se Se. 2 Cry eien eee foto 2 OST. ck 42
Cayenne. (See Amblyomma cajennense.)
fowl. (See Argas miniatus.)
gopher-tortoise. (See Amblyomma tuberculatum. )
Gulf Coast. (See Amblyomma maculatum. )
iguana. (See Amblyomma dissimile. )
Lone Star. (See Amblyomma americanum. )
North American cattle. (See Margaropus annulatus, Boophilus annula-
tus, and Tick, cattle.)
Pacific Coast. (See Dermacentor occidentalis. )
rabbit. (See Hemaphysalis leporis-palustris. )
Rocky Mountain spotted-fever. (See Dermacentor venustus.)
rotund. (See Ixodes kingi.)
spinose ear. (See Ornithodoros megnini. )
tropical horse. (See Dermacentor nitens.)
wood, colloquial name for Dermacentor occidentalis. ...........-...-.-. 189 eas, Seagtations.of fraction. 5... 0:6. SOU POLO US Te En dee ak 26
238
LIFE HISTORY OF NORTH AMERICAN TICKS.
Page. Picks, adaptations of habit... -:ieqivout eee eee Cee 26-27, 28-29 structure,.: - Sk Pee ere tee Se A ea 26, 27-28 bibliography... (os. Fv Se SPS RE FES SE fea Se weoee 205-214 biological study, history Ache seas ue Be es Sere 8 Oe to ee Eo 20-21 bird enemies..~ . .:2. 28 Sb See Se ee eee eee ee 42-43 canmtbalism 22.0.2 06.5 2 <2 Sa RR SUE Ee Cec eee 32 Classification.» 2.2.1... seoP GA cae SSE Dee OPE ne ie 14-17 COMMS CUIMG aos Sc ERE ed Sie ee IE ee mr ere oe 17-18 control. artatietagl =) 1 pet ge Whine Vee A iad hartge NNT cn eden 44 by climatic eorditionss ss. 2s i es Ce eee 41-42 PaPAstes: : ooo Mee a eek ac. Gee Oe ee alee gee 43-44 predacecous enemilegs ob: laxtwae setae hee ea age 42-43 throughimmune raceiofeattleqi 44 Ase. Boe Sore ee ee ee 44 development: 25020222 /y5 3ES es OA A ee ee: 24 dissemination ()2 sy. 42 DA i EN Ce ee SEN Ee Boe 33-34 distribution, geopraphical.:/) 7. Sein Ree oo a ee 21-23 zonal ;:in North America s/o ct ewe iv teat eee eo 21 economic importance... 252-4 Joes ee ees ee eee 18-19 OXCPEMON 22.58 lee 5 SEBO SL Ce ESR ee ee ee 31 fecundation....5 02.02.35 ee ce ee Ee eee 29-31 habits vc Cheese ees os Hes oe ee ee 25-32 history of biological studye aor! 1 PU Het i, OF See 20-21 hostrelationship. .-..2.: 720 dj2s Saas See ee eet See 25-26 hosts, accidental or otherwises2: She Se Se Oe ee 25 investigations in Northwestern States by Bureau of Entomology and Montana Agricultural Experiment Station. ......... 13-14 Texas by Bureauei Entomology so. .i2c. ue. tc ee 13, 14 life history, general)... 5... 2. 22 Se ee a ee eee Menon Lins 24-25 locomotion.:2.0222.2 205 oles 2o se ee ee ae 33-34 mating liabiisy 280002. o34 Yee A ee eee 2 ee 29-31 methods eniployed im .stidies :. - setae see ee ee). ee 35-41 molting habits) sss s05.cHe: beh eu eee ee ea Sa a ae 24-25 MOUMTIMRs Ley lP Sey A book eb 5 3. Se Set Die a 17-18 multipliention. jo). P.oGi8e sees AGA ses S524 52 5 Re oe 32-33 parasites!) 55240 225k EA ee a RRS SA Ie ie A a 43-44 PIOlOZOaN o"2\<j-2 cee ee te a ical a rele 44 periods in life history of economic importance... ..-.....-..---------- 19 predaccous enemies ss. 2 SS a 2a eee ees ae 2 ae ". 42-43 preserving . 225. 3.' 5.255) STO A ees See eee 17-18 protective adaptations of habito il. ses eee ees Se he a Pei 28-29 protozoan parasites. 02120 5 25. ae aL a RS ee 44 rearing methods:..2s..2: 22k. <a ES Seen» Cae See 37-41 reckoning periods In studiesi x2 bsetsut so ee i Lae ees Bee 36-37 temperature in studies) 34/602 705s Jee ee es 35-36 reproductive capacity of species\etudied: 22\ice ses ee! danas Ss seasonal history ..2 6. e= 2.2 ohne aes eye eS ee ee 34-35 secretions. |... sei Qee Te ae eR PE SR a es, ee 31 seed, early information on longewity. . 2./.55. Jee eee ee ee 20 systematic position... \s'-4 22292 ae Se ee eae ee ees 14-17 variation in éolorand size o% 2) heen 8) ee Se 16-17 Toad (Bufo marinus), host of Amblyomma dissimile.........----------------- 131 enemy of Margoropusiannulots australis. ....22. mets eee 122
horned. (See Phrynosoma cornutum. )
Page "Ti SL OF AINDIVGDUNG CAICHNENEE. 060 28 ooo 8 ais nas nn noe odoin a cn peowabictwiccs 152 Ne oc no xed kine athnn -'< naa Stes aap 131 Tortoise, gopher, enemy of Amblyomma tuberculatum.......--..---.-------+-- 30 host of Amblyomma tuberculatum.....-..---.---+.---+-+----- 124 Site Oe AID OUTNS CASALE. oo as ae we ee de 132, 133, 134 ent ke II ORE EAR oe nt ee ee ee 69 Tyegioneneta EE OF PACER, ooo. 5 oe os tee ie 2 bese dey 43 Tireey, moe.e. Demarhysais chordeilia....--...-2..---.----22--2 2-2 ee 97, 101-102 wild, host of- Amblyomma americanum. ......-.-----------+-+--+------- 143 MUPIIIRIMAMEOEOR Ae of ian ln ay aoe ands San HOSA 47 P GEaTe TRRNTALS NERY OF WICKS. 2 52002. 2s ge eee ee oe ke 42 ODES Se St ES PS ee eg oe a re ee 73 Water, submergence, in control of Argas miniatus........--..-.------------- 60 Wax in ears of cattle in control of Ornithodoros megnini.......-..+«----------- 69 icsge), ostiaan Sermupcenior varinvilts. | ec 2-2 ee ee eee ee 191 Wolf, host of Amblyomma americanum. .....---- oad 2 Bist het Sas iat Me 143 eer Sd Ie eS Ao 2) Pm i oa 136 CPLA UNAMID UED AS Mame i oS Sat ead oe 191 2 ES a ee OE Se ee ee ee Lea 83 Woodchuck (see also Marmota flaviventer).
net OF Dermacentor penusius. 252022. cs ba ns e- ee 166, 175, 176 **Wood tick,’’ colloquial name for Dermacentor occidentalis. .......-.....----- 189
Wren, house. (See Troglodytes aedon.) Zapus princeps, host of Dermacentor venustus:......--...--------+0--0---020-- 166
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